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Program
 
Mon Nov 23 2020
Session 1A
Chair: Ward van der Stam
12:00 - 12:05
1A-O2
Staff, nanoGe
nanoGe Presentation
Staff, nanoGe
Authors
nanoGe Staff a
Affiliations
a, nanoGe, Carrer de Campoamor, 73 bajo Izq., València, ES
Abstract
12:05 - 12:10
1A-O1
van der Stam, Ward
Ward van der Stam Presentation
van der Stam, Ward
Authors
Ward van der Stam a
Affiliations
a, Utrecht University, Debye Institute for Nanomaterials Science, NL
Abstract
12:10 - 12:30
1A-K1
Koper, Marc
Understanding competition between CO2 reduction and hydrogen evolution on a gold electrode
Koper, Marc
Authors
Marc Koper a
Affiliations
a, Leiden University, Leiden Institute of Chemistry, Leiden, 2300, NL
Abstract

Understanding competition between CO2 reduction and hydrogen evolution on a gold electrode

In this talk I will summarize our recent efforts in understanding the competition between CO2 reduction and hydrogen evolution on a gold electrode, as studied by rotating ring-disk voltammetry and online Differential Electrochemical Mass Spectrometry. I will show that in neutral media, this competition is extremely sensitive to the electrolyte composition and mass transport conditions. I will also show how by carefully adjusting the CO2 reduction rate to the proton diffusion rate, one can effectively suppress hydrogen evolution in acidic media.

 

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12:30 - 12:40
1A-T1
Pugliese, Silvia
Collège de France
Functionalization of Carbon Nanotubes with Nickel Cyclam for the Electrochemical Reduction of CO2
Pugliese, Silvia
Collège de France
Authors
Silvia Pugliese a, b, Huan Ngoc Tran a, Jérémy Forte c, Sandrine Zanna e, Domenico Grammatico b, d, Bao-Lian Su b, Yun Xu-Li a, Marc Fontecave a
Affiliations
a, Laboratoire de Chimie des Processus Biologiques, UMR CNRS 8229, Collège de France-CNRS-Sorbonne Université, PSL Research University, FR
b, Laboratory of Inorganic Materials Chemistry (CMI), University of Namur, FR
c, Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR 8232 CNRS, FR
d, EPCP, IPREM (UMR-5254), Université de Pau et des Pays de l’Adour, 2 avenue Président Angot, 64053 Pau, FR
e, Chimie ParisTech, PSL Research University, CNRS, 11 rue Pierre et Marie Curie 75231 Paris cedex 05, France, Paris, FR
Abstract

Catalysis for CO2 electroreduction into energy-dense products, such as CO, formic acid, hydrocarbons and alcohols, represents one of the most promising strategies for CO2 utilization. Homogeneous catalysts can be immobilized on heterogeneous conductive supports to generate cathode materials for electrolyzers: such heterogenized molecular systems thus combine the advantages of a solid material (e.g., easy recovery of products and catalysts, efficient electron transfer from the electrode support to the catalyst, high Turnover Numbers) with those of molecular complexes (e.g., synthetic control of the electronic properties and the coordination environment of the active sites). This class of hybrid catalysts for CO2 reduction has been recently described in review articles.[1]–[2]

In this context, [Ni(cyclam)]2+ is known to be a good, stable and selective molecular catalyst for CO2 electroreduction, however, to our knowledge, there is only one precedent for electrode surface modification with [Ni(cyclam)]2+ for electrocatalytic CO2 reduction [3] and this hybrid material proved quite inefficient and poorly selective. Additionally, there is no precedent for the non-covalent immobilization of [Ni(cyclam)]2+ on carbon-based nanostructured electrodes.

In the present research, a novel cyclam derivative carrying a pyrene moiety was readily synthesized for the sake of immobilizing a [Ni(cyclam)]2+ complex at the surface of a carbon-based electrode. The pyrene-modified complex was immobilized on a carbon nanotube-coated gas diffusion electrode using a non-covalent approach and the novel electrode was characterized electrochemically for CO2 electroreduction. The complex proved to be much more active in the immobilized form than under homogeneous conditions, with Faradaic Yields for CO production above 90% and current densities up to 10 mA.cm-2 in acetonitrile/water mixture. The hybrid electrode proved highly stable, leading to impressive turnover numbers (61460 after 4 h electrolysis). This is remarkable since the electrode support is carbon-based and not mercury, so far the best electrode material for CO2 electroreduction catalysed by [Ni(cyclam)]2+ [4]. The present study confirms the benefits of incorporation of molecular catalysts onto electrode surfaces using the pyrene-CNT approach for CO2 electroreduction. Additionally, it shows that the [Ni(cyclam)]2+ complex provides an excellent platform on which further improvements of hybrid electrodes can be brought.

12:40 - 12:55
1A-I1
Manthiram, Karthish
MIT - Massachusetts Institute of Technology
Controlling Interfacial Electron and Atom Transfer Reactions for Chemical Synthesis
Manthiram, Karthish
MIT - Massachusetts Institute of Technology, US
Authors
Karthish Manthiram a
Affiliations
a, MIT - Massachusetts Institute of Technology, Massachusetts Avenue, 77, Cambridge, US
Abstract

Chemical synthesis is responsible for significant emissions of carbon dioxide worldwide. These emissions arise not only due to the energy requirements of chemical synthesis, but since hydrocarbon feedstocks can be overoxidized or used as hydrogen sources. Using renewable electricity to drive chemical synthesis may provide a route to overcoming these challenges, enabling synthetic routes which operate at benign conditions and utilize sustainable inputs. We are developing an electrosynthetic toolkit in which distributed feedstocks, including carbon dioxide, dinitrogen, water, and renewable electricity, can be converted into diverse fuels, chemicals, and materials.

In this presentation, we will first share recent advances made in our laboratory on nitrogen fixation to synthesize ammonia at ambient conditions. Specifically, our lab has investigated a continuous lithium-mediated approach to ammonia synthesis and understood the reaction network that controls selectivity. We have developed non-aqueous gas-diffusion electrodes which lead to high rates of ammonia synthesis at ambient conditions. Then, we will discuss how water can be used as a sustainable oxygen-atom source for epoxidation of olefins as well as related oxygen-atom transfer reactions, providing a route to utilize oxidative equivalents in a water electrolyzer. These findings will be discussed in the context of a broader range of electrosynthetic transformations which could lead to local and on-demand production of critical chemicals and materials.

12:55 - 13:10
Discussion
13:10 - 13:20
1A-T2
de Ruiter, Jim
Utrecht University, The Netherlands
TBA
de Ruiter, Jim
Utrecht University, The Netherlands, NL
Authors
Jim de Ruiter a
Affiliations
a, Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands
Abstract

The Electrochemical Energy Storage and Conversion community aims for the development of better and more efficient catalysts and processes for the use of (renewable) electricity to form or break chemical bonds. This aim is closely associated with the development of novel renewable energy solutions, such as energy storage (electrolyzers), energy conversion (fuel cells and batteries) and chemical production (CO2 reduction and ammonia synthesis). However, efficient communication between the different disciplines (electrochemical synthetic chemists, theoreticians and engineers) is needed in order to develop common technologies that aid the path toward a sustainable future. The main goal of this online ECOCAT conference is to connect the different disciplines within the Electrochemical Energy Storage and Conversion community.

13:20 - 13:30
1A-T3
Vijay, Sudarshan
Technical University of Denmark (DTU)
Investigation of the CO Binding Strength on CO2 to CO Catalysts using Temperature Programmed Desorption and ab initio Molecular Dynamics
Vijay, Sudarshan
Technical University of Denmark (DTU), DK
Authors
Sudarshan Vijay a, Thomas Hogg b, Johan Ehlers b, Henrik Kristoffersen a, Yu Katayama c, d, Yang Shao-Horn c, e, f, Ib Chorkendorff b, Karen Chan a, Brian Seger b
Affiliations
a, Technical University of Denmark, Department of Physics, Fysikvej, 312, Kongens Lyngby, DK
b, Technical University of Denmark, Department of Physics, Fysikvej, 312, Kongens Lyngby, DK
c, Research Laboratory of Electronics, Massachusetts Institute of Technology - USA, Massachusetts Avenue, 77, Cambridge, US
d, Yamaguchi University, Department of Applied Chemistry, Graduate School of Sciences and Technology for Innovation, Tokiwadai, Japan, JP
e, MIT - Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, US
f, Massachusetts Institute of Technology (MIT), Department of Materials Science and Engineering (DMSE), Massachusetts Avenue, 77, Cambridge, US
Abstract

Gold and iron-doped nitrogen graphene (Fe-N-C) are among the most active and selective catalysts for electrochemical CO2 reduction to CO. However, model DFT studies with standard GGA functionals on these materials predict CO poisoning on Fe-N-C and negligible CO coverage on Au, and the latter is contrary to observations in surface-enhanced spectroscopic experiments. Furthermore, the interfacial electric field and solvation can affect the binding strength, and these effects remain an open challenge for ab initio studies. To determine the CO adsorption energy and to assess the accuracy of DFT-GGA results, we return to a surface science experiment: temperature programmed desorption (TPD). By fitting TPD spectra to a model first order kinetic expression including the configuration entropy of the adsorbate, we determine the adsorption energy and equilibrium coverage of *CO on Au step facets [1] and Fe-N-C [2]. We find that the adsorption energies on these materials are remarkably similar, in contrast to DFT-GGA predictions. The results indicate that hybrid functionals are needed on Fe-N-C in order to accurately capture the binding strength. To investigate the impact of the electrochemical environment, we compare water adsorption energies from TPD with ab-initio molecular dynamics (AIMD) calculations. We find that the competition between water and CO adsorption can significantly affect the CO adsorption strength and result in different binding sites for *CO on Au in gas phase and electrochemical environments.

13:30 - 13:45
1A-I2
Sinton, David
Electrocatalytic Systems for CO2 conversion to C2 products
Sinton, David
Authors
David Sinton a
Affiliations
a, University of Toronto, King's College Road, 10, Toronto, CA
Abstract

Renewably powered CO2 electrocatalysis presents an opportunity to de-carbonize chemical production. Ultimate application of CO2 reduction will require electrocatalytic systems that provide  reactants, electrons, and products at high rate and efficiency, and that are compatible with upstream and downstream processes. I will outline our progress on membrane electrode assembly based cells to meet this challenge. To accommodate O2 impurities from upstream processes we develop a hydrated ionomer catalyst coating that selectively slows O2 transport and stabilizes the copper catalyst. To increase reaction rate and energy efficiency we develop an adlayer catalyst strategy that increases local CO2 availability and tunes intermediate adsorption for ethylene production. For ethanol production we focus on minimizing product cross-over to the anode, and achieve ethanol production in excess of 10wt% - comparable to bio-ethanol production and compatible with downstream processes. Lastly I will highlight learnings, challenges and opportunities arising from our system scaling efforts in the 2020 Carbon XPRIZE competition.

13:45 - 13:55
Discussion
13:55 - 14:10
Break
Session 1B
Chair: Marta Costa Figueiredo
14:10 - 14:15
1B-O1
Costa Figueiredo, Marta
Marta Costa Figueiredo Presentation
Costa Figueiredo, Marta
Authors
Marta Costa Figueiredo a
Affiliations
a, Eindhoven University of Technology (TU/e), PO Box 513, Eindhoven, 5600, NL
Abstract
14:15 - 14:30
1B-I1
Katsounaros, Ioannis
Tracking Reaction Products in Real Time
Katsounaros, Ioannis
Authors
Ioannis Katsounaros a
Affiliations
a, Forschungszentrum Jülich GmbH, Helmholtz-Institut Erlangen-Nürnberg for renewable energy, DE
Abstract

The classical way to characterize reaction products in electrochemistry involves steady-state electrolysis combined with intermittent or offline product determination, for example with chromatography, nuclear magnetic resonance etc. These methods are excellent to quantify products in terms of faradaic efficiencies and reaction rates, but they offer temporal resolution in the order of several minutes. Therefore, it is not possible to determine the product formation under dynamic conditions. We recently developed an internationally unique method to characterize the products of electrochemical reactions at the time they are formed, the electrochemical real-time mass spectrometry (EC-RTMS) [1-4]. Contrary to previous approaches, EC-RTMS is not limited by the vapor pressure of analytes or the presence of non-volatile salts. I will present he basic principles of EC-RTMS, together with its capabilities exemplified for some electrochemical reactions such as the reduction of carbon dioxide or the oxidation of alcohols.

14:30 - 14:40
1B-T1
Wenderich, Kasper
University of Twente
The Benefits and Feasibility of Anodic H2O2 Production in (Photo)electrochemical Water Splitting: a Techno-Economic and Experimental Analysis
Wenderich, Kasper
University of Twente, NL
Authors
Kasper Wenderich a, Birgit Nieuweweme a, Marjolijn Katerberge a, Guido Mul a, Bastian Mei a
Affiliations
a, Photocatalytic Synthesis (PCS) Group, Faculty of Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, NL
Abstract

Photoelectrochemical (PEC) or photovoltaic-driven electrochemical (PV-E) water splitting is considered a promising, renewable technique for the production of the green fuel hydrogen (H2). Nevertheless, a major bottleneck is that H2 production through (photo)electrochemical water splitting is financially not as attractive as H2 generation through steam methane reforming [1].

In this work, we discuss the partial oxidation of water to the commodity chemical hydrogen peroxide (H2O2) (E0 (H2O2/H2O) = +1.78 V vs RHE) as a financially promising substitute for anodic water oxidation to O2 [2,3]. Particularly, we will consider two scenarios: PEC and PV-E H2O2 production.
First, we demonstrate that the H2 price can be lowered significantly compared to ‘classic’ water splitting for a PEC system using a techno-economic analysis. Here we consider (i) a near-optimal scenario and (ii) a literature-based state-of-the-art scenario. It will be shown that H2 production through steam methane reforming is even financially outcompeted.
Second, we will focus on PV-E systems and discuss on an experimental basis the suitability of various electrode materials for anodic H2O2 production. We demonstrate that boron-doped diamond yields promising results, reaching Faradaic efficiencies to H2O2 over 30% and H2O2 production rates slightly over 4.5 μmol min-1 cm-2. Finally, implementing the obtained experimental results in (a slightly altered version of) our techno-economic model, we will discuss the most important areas where research should be pursued in to make anodic H2O2 production even more attractive.

14:40 - 14:55
1B-I2
Garcia, Amanda
University of Amsterdam
Insights into C-C Coupling in CO2 Electroreduction towards C4 Product
Garcia, Amanda
University of Amsterdam, NL
Authors
Amanda Garcia a
Affiliations
a, Van't Hoff Institute for Molecular Science - University of Amsterdam, NL
Abstract

The development of green industrial processes has been attracting more attention in the last years and it requires renewable energy sources. Large-scale electrification of the energy and chemistry sectors is a crucial condition for the transition from a society based on fossil resources to a sustainable society based on renewable building blocks. Transformation of CO2 into chemicals has been intensively studied over the past decades because this molecule can be used as C1 feedstock in electro-organic synthesis due to its abundant, cheap, renewable and non-toxic nature1. Of particular interest of this molecule is the synthesis of two- to four-carbon atom products (C2-C4). Concerning the synthesis of C2-C4 products, tartaric acid (TTA) attracts attention because it is an important product used in the textile printing, dyeing, pharmaceutical and food industries2. In the past years, the price of TTA and its salts has varied as much as 50 %, as might be expected when the source of the raw material is a by-product of another industry.

Herein we describe a study of the electrochemical reduction of oxalic and glyoxylic acids towards a feasible green and sustainable production of tartaric acid in aqueous and/or acetonitrile solvent using silver and lead electrodes.

Our results show that on the silver electrode, for both oxalic acid and glyoxylic acid, the reduction reaction is more favorable towards the dimerization step, leading to tartaric acid, due to the increase in the local pH, while on the lead electrode the step involving the protonation of the intermediate is more favorable, leading to the formation of glycolate.

Techno-Economic Analysis shows that tartaric acid production from glyoxylic acid and from oxalic acid via electrochemical synthesis can be a potential process at an industrial scale. In the present case, the oxygen evolution reaction was chosen as the reaction at the other electrode for practical reasons, but oxygen is a low-value product. Another anodic reaction with a more valuable oxidation product can be selected to increase the profitability of the overall electrochemical process, andthereby decrease the total production costs of tartaric acid.

 

14:55 - 15:10
Discussion
15:10 - 15:20
1B-T2
Biemolt, Jasper
University of Amsterdam
Order vs Chaos; different phases in N-doped carbons and their oxygen reduction capability
Biemolt, Jasper
University of Amsterdam, NL
Authors
Jasper Biemolt a, Gadi Rothenberg a, Ning Yan a
Affiliations
a, Van't Hoff Institute for Molecular Science - University of Amsterdam, NL
Abstract

Fuel cells are the upcoming alternative for the combustion engine. Using hydrogen and oxygen to produce water and electricity, they promise higher efficiencies and no pollution. These green electrochemical reactions, hydrogen oxidation reaction and oxygen reduction reaction (ORR) are excellently catalyzed by noble metals. However, these elements are costly and scarce, limiting the use of fuel cells to only novelty projects. For large scale application, affordable and abundant electrocatalysts are a must.

As an alternative, we and others developed N-doped carbons, promising catalysts at a fraction of the price of noble metals and abundant enough to use in every imaginable application.[1,2] Inherently, N-doped carbons consist of defect rich disordered amorphous domains and ordered graphitic domains, both active in ORR. But which domain is more active for ORR, amorphous or graphitic? An important question, as decreasing inactive material and thus decreasing electrode area is the difference between hydrogen fuel cells fitting only Hummers or also fitting Smarts.

To answer the question, we changed the ratios between these phases in our well characterized carbon. Using this method, we got three valuable insights. First, as promised we showed which phase N-doped carbon phase is more ORR active. But we did not stop there. We also aimed to understand the post-synthesis modifications and how these affected the N-doped carbon morphology and surface structure. Lastly, we showed that, just like numbers without context, synthesis/modifications without understanding provide wrong conclusions.

15:20 - 15:30
1B-T3
Davies, Bethan
Electrocatalytic Synthesis of Dimethyl Carbonate
Davies, Bethan
Authors
Bethan Davies a, Maria Escudero-Escribano a
Affiliations
a, Department of Chemistry, Nano-Science Center, University of Copenhagen, Denmark, Universitetsparken, 5, København, DK
Abstract

DMC is a valuable chemical used on industrial scale for both production (e.g. carbonylation reactions) and in end products (e.g. paints and batteries). DMC is currently formed by thermal catalysis but can be formed electrocatalytically, it is a carbonylation product of methanol1, formed electrochemically by the reaction 2CH3OH + CO à (CH3O)2CO + 2H+ + 2e-.

The purpose of the work is to understand the fundamental aspects of the carbonylation reaction over an electrode surface, i.e. by heterogeneous electrocatalysis, rather than homogeneous or indirection electrosynthesis. Knowing the steps of formation and the reaction intermediates involved will allow us to develop the catalytic system in a rational manner as well as apply the knowledge to later reactions of interest (e.g. carbonylation of other alcohols, such as phenol, to form valuable products). Understanding the active site and mechanism of the reaction is paramount for rational optimisation strategies.

Different transition metals (Cu, Au, Pt) have been tested for their activity towards DMC production1,2,3. Au is more active than Pd in terms of current efficiency as well as current density (Figure 1), whereas Cu catalysis DMC synthesis via an inefficient solution phase mechanism. We have used different techniques to understand catalyst activity: in situ infrared spectroelectrochemistry (in situ FTIR) and headspace gas chromatography mass spectrometry (HS-GC-MS). The results that we have obtained so far have been discussed in combination with a theoretical analysis which has helped us understand the mechanisms involved. Further development is underway for optimising the catalyst as well as reactor system.

[1] Šarić, M., Davies, B.J.V. et al, Green Chem., 2019, 21, 6200-6209
[2] Davies, B.J.V. et al, ACS Catal., 2019, 9, 2, 859-866
[3] Davies, B.J.V. et al, J. Phys. Chem. C, 2019, 123, 20, 12762-12772

15:30 - 15:50
1B-K1
Sargent, Edward
University of Toronto
Progress and next steps in CO2 reduction to chemicals
Sargent, Edward
University of Toronto, CA

Ted Sargent received the B.Sc.Eng. (Engineering Physics) from Queen's University in 1995 and the Ph.D. in Electrical and Computer Engineering (Photonics) from the University of Toronto in 1998. He holds the rank of Professor in the Edward S. Rogers Sr. Department of Electrical and Computer Engineering at the University of Toronto, where he holds the Canada Research Chair in Nanotechnology and serves as a KAUST Investigator. His book The Dance of Molecules: How Nanotechnology is Changing Our Lives (Penguin) was published in Canada and the United States in 2005 and has been translated into French, Spanish, Italian, Korean, and Arabic. He is founder and CTO of InVisage Technologies, Inc. He is a Fellow of the AAAS “...for distinguished contributions to the development of solar cells and light sensors based on solution-processed semiconductors.” He is a Fellow of the IEEE “... for contributions to colloidal quantum dot optoelectronic devices.”

Authors
Edward Sargent a
Affiliations
a, Department of Electrical and Computer Engineering, University of Toronto, Canada, King's College Road, 10, Toronto, CA
Abstract

I will review recent progress in CO2 reduction electrocatalysis toward sustainable chemicals. This will include a discussion of systems that enable the needed high rate of electroproduction in order to render capital costs acceptable. It will also include work on the catalysts and their electrolyte that are capable of producing a relatively high selectivity towards a desired product, such as for example ethylene. Overall I will look at further progress needed to achieve high CO2 utilization, and - crucially - to continue to increase energy efficiency on the path towards prospective technoeconomic viability. The approaches used will include computational studies as well as nanomaterials synthesis and in situ spectroscopies.

15:50 - 16:00
Discussion
 
Tue Nov 24 2020
Session 2A
Chair: Núria López
12:00 - 12:05
2A-O2
Staff, nanoGe
nanoGe Presentation
Staff, nanoGe
Authors
nanoGe Staff a
Affiliations
a, nanoGe, Carrer de Campoamor, 73 bajo Izq., València, ES
Abstract
12:05 - 12:10
2A-O1
López, Núria
Núria López Presentation
López, Núria
Authors
Núria López a
Affiliations
a, Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avinguda dels Països Catalans, 16, Tarragona, ES
Abstract
12:10 - 12:30
2A-K1
Chan, Karen
Technical University of Denmark (DTU)
Surface charge density as a descriptor for the driving source in electrochemical processes - what it means for our DFT simulations and for electrochemical CO2 reduction
Chan, Karen
Technical University of Denmark (DTU), DK
Authors
Karen Chan a
Affiliations
a, Technical University of Denmark (DTU), DK
Abstract

Electrochemical CO2R is a particularly challenging process from both modelling and experimental perspectives.  The challenge arises from the complexity of its reaction network and the sensitivity of its activity and selectivity to the electrolyte composition and the associated interfacial field effects. In this talk, I will first discuss developments in methods to model the electrochemical interface - the accuracy of widely applied continuum approximations of the electrolyte, as well as a new unified approach to obtain electrochemical barriers from both explicit and implicit solvent simulation approaches.  In particular I emphasize that the surface charge gives the most appropriate proxy of the local potential (vs. the traditionally considered work function).  Then, I will discuss the impact of the electrolyte composition - pH and ions - on electrochemical CO2R activity of both transition metals as well as supported single atom catalysts.  Finally, I discuss the implications of our findings for electrocatalyst design and electrolyte engineering.

12:30 - 12:40
2A-T1
Rossi, Kevin
Ecole Polytechnique Federale de Lausanne (EPFL)
Multiscale design of nanocatalysts for electrochemical reactions, the case of Pt nanoparticles for Oxygen Reduction
Rossi, Kevin
Ecole Polytechnique Federale de Lausanne (EPFL), CH
Authors
Kevin Rossi a
Affiliations
a, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, CH
Abstract

We present a novel multiscale numerical approach to estimate in an efficient, accurate, and high-throughput fashion the current density and mass activity of individual Pt nanoparticles as well as morphologically diverse but size-selected samples for Oxygen Reduction. In this newly developed framework we adapt the computational hydrogen electrode model to forecast currents from reactions taking place at any active site, by means of a statistical learning approach and a geometrical descriptor that bridges the active site topological and catalytic properties.

By exploiting the above framework we then propose specific design rules of Pt-nanoparticles for the electrochemical reduction of molecular oxygen identifying the size-range up to 5.5 nm as the one where structural effects are fundamental and can not be neglected. We confirm the peak of the activity of defected and concave polyhedra at 2-3 nm whilst spherical but amorphous isomers are the most active between 3-5 nm, with a large mass activity, 2.7 A/mg. Finally, we discuss possible discrepancies in the experimentally measured mass activity of size-selected samples in terms of the different distributions of Pt-isomers in each specimen.

The extension of our model to other electrochemical reactions will be also discussed if time allows.

12:40 - 12:55
2A-I1
Dattila, Federico
ICIQ.Institute of Chemical Research of Catalonia - ICREA, Spain
Active Ensembles and a New Selective Intermediate for CO2 Reduction on Oxide-Derived Copper Catalysts
Dattila, Federico
ICIQ.Institute of Chemical Research of Catalonia - ICREA, Spain, ES

Federico Dattila is an Italian physicist interested in renewable energies and environmental sustainability. Though having a humanistic high school background, he got a Bachelor of Science (2015) and a Master of Science (2017) degree in Physics at University of Turin (Italy). The master thesis project was developed in collaboration with Chalmers University of Technology through the ERASMUS programme (Gothenburg, Sweden, spring 2017). In addition, he actively promoted sustainability in his university through the foundation of greenTO, a student association (2016). He is currently an Early Stage Researcher (ESR) within the ELCoREL Innovative Training Network at the Institute of Chemical Research of Catalonia (ICIQ, Tarragona, Spain) under the supervision of Prof. Núria López.

Authors
Federico Dattila a, Rodrigo Garcı́a-Muelas a, Núria López a
Affiliations
a, ICIQ.Institute of Chemical Research of Catalonia - ICREA, Spain, ES
Abstract

Copper catalysts are unique in enabling CO2 reduction toward C2+ products, such as ethylene, ethanol and n-propanol[1]. C2+ product distribution varies significantly over time and depends on the catalysts’ synthesis[2]. While Cu foil produces mainly ethylene with oxygenates as side-products, oxide-derived copper have the exclusive capacity of converting CO2 and CO to ethanol at high Faradaic efficiencies and low overpotentials[3]. Polarized copper sites, residual oxygen, defects, gran boundaries, and high electrochemical surface area have been deemed responsible for the high CO2 reduction activity and the more favorable CO-CO dimerization step expected for these catalysts. Specific active sites toward ethylene, ethanol and 1-propanol have been identified for oxide-derived systems by isotopic labeling[4], however they have not beed characterized yet.  

Here, by means of ab initio molecular dynamics simulations on seven oxygen-depleted models derived from Cu2O and Cu pristine structures, we identified the main ensembles which control the catalytic performance of oxide-derived copper. Upon surface reconstruction and independently from the starting depletion geometry, copper can be classified in three main classes depending on its local coordination and charge: metallic Cu0, polarized Cuδ+, and oxidic Cu+, respectively coordinated to 0, 1 and 2 oxygens. These three species form 14 ensembles, such as 4- and 6-coordinated Cu adatoms, Cu3δ+O3, reconstructed (111), (110) and (100) crystalline domains and near-surface oxygens. Together with the high atomic roughness, low coordinated Cu adatoms and polarized sites are responsible for tethering CO2 and therefore improving CO2 reduction activity. Metastable oxygens and metallic fcc-(111) or (100)-like Cu facets promote CO–CO dimerization step via a deprotonated glyoxylate species, whose formation is theormodynamically favored and presents a negligible kinetic barrier. Characterized by vibrational fingerprints in agreement with spectroscopic features of oxide-derived copper under CO2 reduction conditions, this new chemical species could be the elusive intermediate which enables selective C2+ production at low onset potentials[2]. This study[5] provides a new theoretical set of concepts for modeling complex structural rearrangements driven by the high surface polarization characteristic of CO2 reduction conditions and suggest guidelines for new synthetic protocols for the creation of selective catalysts toward ethylene and oxygenates.

12:55 - 13:10
Discussion
13:10 - 13:20
2A-T2
Heenen, Hendrik H
Technical University of Denmark (DTU)
The electrified Cu/aqueous interface under alkaline conditions: Converging experiment and theory via kinetics
Heenen, Hendrik H
Technical University of Denmark (DTU), DK
Authors
Hendrik H Heenen a, Aarti Tiwari a, Anton Simon Bjørnlund a, Henrik H Kristoffersen a, Sebastian Horch a, Karen Chan a
Affiliations
a, Technical University of Denmark, Department of Physics, Fysikvej, 312, Kongens Lyngby, DK
Abstract

This work was supported by Grant 9455 from VILLUM FONDEN and the European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie Grant Agreement 713683.A persistent challenge in electrocatalysis is the limited understanding of the microscopic processes occurring at electrified solid/electrolyte interfaces. Even single-crystal studies which treat well-defined surfaces are often challenged to provide a deeper insight due to a lack of sensitive analytical methods. Atomistic simulations potentially fill this gap of missing analytics but may not align with experimental observations. Possible discrepancies may arise not only from the absence of the necessary complexity in computational model systems but also due to the limitations in a thermodynamic description. Here we present a rigorous joint experimental–theoretical study on the single-crystal (SC) Cu/aqueous interface based on sufficiently clean experiments and a kinetic description of the electrochemical processes in our theoretical model. In the direct comparison between simulated and experimentally measured voltammograms, we achieve agreement within typical computational uncertainty. The experimental and computational consensus allows us to unequivocally identify the *OH adsorption feature in the fingerprint region of Cu(110), Cu(100), and Cu(111) SCs under alkaline conditions. In our computational treatment we find the inclusion of hydrogen evolution reaction kinetics to be crucial for an accurate steady-state description that gives rise to a negligible H* coverage on the Cu surface [1]. In contrast, a purely thermodynamic description of the H* coverage through a Pourbaix analysis would incorrectly lead to a H* adsorption peak. We further demonstrate how we can achieve near quantitative agreement of peak positions between theory and experiment via sensitive improvements of the solvation energies using corrections predicted by molecular dynamics simulations [2]. Our work demonstrates the importance of reaction kinetics to elaborate on the electrocatalysts’ surface composition and how a refined description of the electrochemical interface, particularly through solvation, improves accuracy.

13:20 - 13:30
2A-T3
Melander, Marko
University of Jyväskylä, Finland
Electrocatalytic thermodynamics and kinetics at constant electrode potentials: The grand canonical ensemble approach
Melander, Marko
University of Jyväskylä, Finland, FI

Dr. Marko M. Melander is an Academy of Finland Postdoctoral researcher at the University of Jyväskylä, Finland. Before obtaining his current position in 2017, he obtained a Ph.D. in physical and computational chemistry from Aalto University in 2015 after which he joined the Atomic Scale Modelling and Materials group at DTU. His research focuses on development and application of theory and computational methods to study (proton-coupled) electron transfer in electrochemical systems, heterogeneous catalysis of complex systems, and multiscale modelling. 

Authors
Marko Melander a
Affiliations
a, University of Jyväskylä, Finland, Department of Chemistry/Nanoscience Center, Jyväskylä, FI
Abstract

Using the electrode potential and electrolyte to manipulate reaction thermodynamics and kinetics forms the backbone of all electrochemistry and electrocatalysis. Especially important reactions to understand are proton-coupled electron transfer (PCET) reactions forming the mechanistic basis of e.g. oxygen, CO2, and N2 reduction and hydrogen evolution reactions. While clever and cheap schemes for evaluating electrochemical thermodynamics and kinetics have been developed, a rigorous treatment is needed to test the accuracy and to define well-controlled computational models.

In my contribution I will present a rigorous theory and numerical techniques to simulate electrochemical solid-liquid interfaces using grand canonical ensemble density functional theory (GCE-DFT) [1] – this approach provides an exact theory and well-defined approximations to compute thermodynamics as a function of the electrode potential and electrolyte concentration. Besides thermodynamics, I will present the newly established generally valid GCE rate theory (GCE-RT) to address PCET reaction kinetics as a function of the electrode potential.[2,3] The GCE-RT can account for (non-adiabatic) proton and electron tunneling which may significantly contribute to PCET kinetics and long-range electron transfer, respectively.[3] Besides theory, I will present how the thermodynamics, kinetics, and nuclear quantum effects of a gold-catalyzed Volmer reaction can be addressed and understood from the atomic scale with GCE-DFT and GCE-RT[2-3]. I will also show how GCE-DFT can be used for parametrizing effective Hamiltonians for predicting and explaining electron transfer kinetics and experimental measurements (in preparation).

The presentation provides an account on the recent theoretical and methodological developments in using constant potential, grand canonical ensemble DFT for simulating electrochemical interfaces and reactions. These developments enable simulating both the thermodynamics and kinetics of electrochemical reactions, including both classical adiabatic inner-sphere reactions as well as e.g. outer-sphere reactions, non-adiabaticity, and nuclear tunneling at the DFT level.

 

13:30 - 13:45
2A-I2
Ulissi, Zachary
Carnegie Mellon University
The Open Catalyst 2020 (OC20) Dataset and Community Challenges
Ulissi, Zachary
Carnegie Mellon University, US
Authors
Zachary Ulissi a
Affiliations
a, Carnegie Mellon University, Department of Materials Science and Engineering, Pittsburgh, 0, US
Abstract

The Open Catalyst Project aims to develop new ML methods and models to accelerate the catalyst simulation process for renewable energy technologies and improve our ability to predict activity/selectivity across catalyst composition. To achieve that in the short term we need participation from the ML community in solving key challenges in catalysis. One path to interaction is the development of grand challenge datasets that are representative of common challenges in catalysis, large enough to excite the ML community, and large enough to take advantage of and encourage advances in deep learning models. Similar datasets have had a large impact in small molecule drug discovery, organic photovoltaics, and inorganic crystal structure prediction. We present the first open dataset from this effort on thermochemical intermediates across stable multi-metallic and p-block doped surfaces. This dataset includes full-accuracy DFT calculations across 53 elements and their binary/ternary materials, various low-index facets. Adsorbates span 56 common reaction intermediates with relevance to carbon, oxygen, and nitrogen thermal and electrochemical reactions. Off-equilibrium structures are also generated and included to aid in machine learning force field design and fitting. Collectively, this dataset represents the largest systematic dataset that bridges organic and inorganic chemistry and will enable a new generation of catalyst structure/property relationships. Fixed train/test splits that represent common chemical challenges and an open challenge website will be discussed to encourage competition and buy-in from the ML community.

13:45 - 13:55
Discussion
13:55 - 14:10
Break
14:10 - 16:00
ePoster Session
 
Wed Nov 25 2020
Session 3A
Chair: Sixto Gimenez Julia
12:00 - 12:05
3A-O2
Staff, nanoGe
nanoGe Presentation
Staff, nanoGe
Authors
nanoGe Staff a
Affiliations
a, nanoGe, Carrer de Campoamor, 73 bajo Izq., València, ES
Abstract
12:05 - 12:10
3A-O1
Gimenez Julia, Sixto
Sixto Gimenez Julia Presentation
Gimenez Julia, Sixto
Authors
Sixto Gimenez Julia a
Affiliations
a, Universitat Jaume I, Institute of Advanced Materials (INAM) - Spain, Avinguda de Vicent Sos Baynat, Castelló de la Plana, ES
Abstract
12:10 - 12:30
3A-K1
Strasser, Peter
Technical University of Berlin (TU)
Active Structure, Reactivity, and Mechanism of the Electrocatalytic Oxygen Evolution on Layered Double Hydroxides
Strasser, Peter
Technical University of Berlin (TU), DE

Peter Strasser is the chaired professor of �Electrochemistry for energy conversion and storage� at the Chemical Engineering Division of the Department of Chemistry at the Technical University of Berlin. Prior to his appointment, he was Professor at the Department of Chemical and Biomolecular Engineering at the University of Houston. Before moving to Houston, Prof. Strasser served as Senior Member of staff at Symyx Technologies, Inc., Santa Clara, USA. In 1999, Prof. Strasser earned his doctoral degree in Physical Chemistry and Electrochemistry from the �Fritz-Haber-Institute� of the Max-Planck-Society, Berlin, Germany, under the direction of the 2007 Chemistry Nobel Laureate, Professor Gerhard Ertl. In the same year, he was awarded the �Otto-Hahn Research Medal� by the Max-Planck Society. In 1996, Dr. Strasser was visiting scientist with Sony Central Research, Yokohama, Japan. He studied chemistry at Stanford University, the University of Tuebingen, and the University of Pisa, Italy. Professor Strasser is interested in the fundamental Materials Science and Catalysis of electrified liquid solid interfaces, in particular for renewable energy conversion, energy storage, production of fuels and chemicals.

Authors
Peter Strasser a
Affiliations
a, Technical University of Berlin (TU), Straße des 17. Juni, Berlin, DE
Abstract

Bimetallic MA(II)MB(III) layered double hydroxides (LDHs), in particular Fe(III) containing ones, are among the most active and widely studied catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. However, little is known about the dynamic structural transformation of the inactive alpha-phase to the catalytically active gamma-phase under concomitant ion exchange.

I will highlight recent advances of our understanding of the active catalyst structure, the reactivity, and the likely molecular reaction mechanism of the electrocatalytic evolution of molecular of oxygen on M(II)M(III) layered double hydroxide materials. Focus is placed on NiFe and CoFe catalyst using operando X-ray and DEMS analysis, coupled to ab Initio Molecular Dynamics (AIMD) modeling [1].

12:30 - 12:40
3A-T1
Liang, Qiuhua
DIFFER – Dutch Institute for Fundamental Energy Research, the Netherlands
Monolayer Nitrides Doped with Transition Metals as Efficient Catalysts for Water Oxidation: the Singular Role of Nickel
Liang, Qiuhua
DIFFER – Dutch Institute for Fundamental Energy Research, the Netherlands, NL

Qiuhua Liang is a doctoral candidate at the Department of Applied Physics at Eindhoven University of Technology (TU/e) in the Netherlands. She was born in Guangxi, P. R. China. She studied microelectronics at the Guilin University of Electronic Technology in China. In September 2017, she was enrolled as a doctoral candidate supported by China Scholarship Council (CSC). Her PhD research focuses on the investigation of oxygen evolution reaction (OER) on nitrides and oxides. She is undertaking research under the supervision of Dr. Anja Bieberle-Hütter at the electrochemical materials and interface (EMI) in Dutch Institute for Fundamental Energy Research (DIFFER) and Prof. Geert Brocks at the Materials Simulation and Modelling (MSM). Her current work including 1) The oxygen evolution reaction (OER) of the transition metal oxides; 2) the excited state simulations of OER process on the hematite surface.

Authors
Qiuhua Liang a, Geert Brocks b, Xueqing Zhang a, Anja Bieberle-Hütter a
Affiliations
a, DIFFER – Dutch Institute for Fundamental Energy Research, the Netherlands, De Zaale, 20, Eindhoven, NL
b, Computational Materials Science, Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, The Netherlands, 7500 AE Enschede, NL
Abstract

Exploration of precious-metal-free catalysts for water splitting is of great importance in developing renewable energy conversion and storage technologies. Here, we investigate the link between the oxygen evolution reaction (OER) activities and the electronic properties of pure and first-row transition-metal-doped AlN and GaN monolayers. We find that Ni-doped layers are singularly appealing because they lead to a low overpotential (0.4 V). Early transition-metal dopants bind the intermediate species OH or O too strongly. The late transition-metal dopants Cu and Zn bind intermediate species too weakly which leads to large overpotentials or to no OER activity at all. Ni dopant breaks this trend and stabilizes instead the OOH adsorbant which can be correlated with a switch from a high- to a low-spin state of the dopant atom. This ability to change spin states offers an exciting ingredient for the design of OER catalysts [1].

12:40 - 12:55
3A-I1
Haussener, Sophia
Ecole Polytechnique Federale de Lausanne (EPFL)
Multi-physical transport in structured (photo)electrodes
Haussener, Sophia
Ecole Polytechnique Federale de Lausanne (EPFL), CH

Sophia Haussener is a Professor heading the Laboratory of Renewable Energy Science and Engineering at the Ecole Polytechnique Federale de Lausanne (EPFL). Her current research is focused on providing design guidelines for thermal, thermochemical, and photoelectrochemical energy conversion reactors through multi-physics modelling and experimentation. Her research interests include: thermal sciences, fluid dynamics, charge transfer, electro-magnetism, and thermo/electro/photochemistry in complex multi-phase media on multiple scales. She received her MSc (2007) and PhD (2010) in Mechanical Engineering from ETH Zurich. She was a postdoctoral researcher at the Joint Center of Artificial Photosynthesis (JCAP) and the Lawrence Berkeley National Laboratory (LBNL) between 2011 and 2012. She has published over 70 articles in peer-reviewed journals and conference proceedings, and 2 books. She has been awarded the ETH medal (2011), the Dimitris N. Chorafas Foundation award (2011), the ABB Forschungspreis (2012), the Prix Zonta (2015), the Global Change Award (2017), and the Raymond Viskanta Award (2019), and is a recipient of a Starting Grant of the Swiss National Science Foundation (2014).

Authors
Sophia Haussener a
Affiliations
a, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, CH
Abstract

The morphology of semiconductor photoelectrodes and metallic electrodes significantly affects the performance of (photo)electrochemical devices. Complex anisotropic morphologies are important for overcoming performance limiting bulk transport properties of semiconductor materials or enhancing the selectivity of CO2 reduction electrodes, but are often also an unintended outcome of the fabrication process. A better understanding of morphology-induced transport limitations of (photo)electrodes is needed to better understand the kinetics, degradation, and transport limitations, and to subsequently guide mesostructured design and performance optimization. We use direct pore-level simulations for the coupled transport characterization of mesostructured (photo)electrodes. I will introduce and discuss four short examples to show the importance of local heterogeneities and reaction environment on the performance and degradation: i) stochastic, particle-based lanthanum titanium oxynitride (LTON) photoanodes for water oxidation, ii) degradation in porous photoanodes made of compound semiconductors, iii) structured, inverse opal silver electrodes for CO2 reduction, and iv) CO2 reduction in gas diffusion electrodes.

12:55 - 13:10
Discussion
13:10 - 13:20
3A-T2
Goyal, Akansha
Leiden University
The Role of Cations and Electrolyte pH in the Hydrogen Evolution Reaction on Au in Alkaline Media
Goyal, Akansha
Leiden University, NL
Authors
Akansha Goyal a, Marc T.M. Koper a
Affiliations
a, Leiden University, Leiden Institute of Chemistry, Leiden, 2300, NL
Abstract

In this work, we study the role of alkali metal cation concentration and electrolyte pH on the kinetics of hydrogen evolution reaction (HER) at Au electrodes in order to discern a clear activity descriptor for this reaction under alkaline conditions. We find that at moderately alkaline pH (pH =11), increasing cation concentration significantly enhances the HER activity on Au electrodes (reaction order » 0.5). We propose that the cations near the interface interact favorably with the transition state of the rate-determining Volmer step by stabilizing the (partially) negative hydroxide which is being split off from the reacting water molecule (*H--OHδ---cat+). Remarkably, at higher pH, the effect of the concentration of alkali cations is diminished, and it is even negative at pH=13. Furthermore, capacitance curves obtained via impedance spectroscopy suggest that the electrolyte pH also influences the near-surface composition of the electrolyte such that an increasing electrolyte pH leads to a corresponding increase in the near-surface cation concentration. This results in an apparent pH dependence for the HER activity on the Au electrodes where synonymous to the cation concentration effect, saturation is observed at extreme pH values (pH 13 to pH 14). We attribute the saturation and even inhibitive effects observed at high pH and at high cation concentration to a blockage of the surface by cations beyond a threshold concentration.

This work shows that the electrolyte pH and the near-surface cation concentration are inter-dependent parameters, which cannot be de-coupled while probing the metal-electrolyte interface in the alkaline media. Hence, our work provides foundational insights on the complex molecular origins behind the pH dependence of HER, and we believe that these insights will be instrumental in guiding the design of optimized catalyst-electrolyte conditions for HER in the alkaline media. Finally, we also extend the understanding gained from these studies to rationalize the unusual role of mass transport in determining the HER activity by controlling the local pH using rotating disk electrode voltammetry (1).

13:20 - 13:30
3A-T3
Grochowska, Katarzyna
The Szewalski Institute of Fluid-Flow Machinery Polish Academy of Sciences
Laser-assisted Fabrication Route of TiO2-Au Hybrid Materials for Applications in Water-splitting
Grochowska, Katarzyna
The Szewalski Institute of Fluid-Flow Machinery Polish Academy of Sciences, PL
Authors
Katarzyna Grochowska a, Nikolay Nedyalkov b, Jakub Karczewski c, Łukasz Haryński a, Gerard Śliwiński a, Katarzyna Siuzdak a
Affiliations
a, The Szewalski Institute of Fluid-Flow Machinery Polish Academy of Sciences, Generała Józefa Fiszera, 14, Gdańsk, PL
b, Bulgarian Academy of Sciences, Institute of Electronics, BG
c, Gdansk University of Technology, PL
Abstract

Novel and efficient devices taking advantage of renewable energy sources, supercapacitors, water-splitting devices and high-capacity batteries, as well as various sensors, are hot topics within the society, and at the same time are challenges for scientific community. The latest approaches and dynamic development in those fields benefit from materials research at nanometre-size level. Significant efforts are being aimed especially at fabrication of functional nanomaterials where two materials are combined and synergistic effect is observed which is atypical for the single elements [1, 2]. To fit in with the latest trends, we combined titania nanotubes (TiO2NTs) with gold species in order to obtain photoactive material. Moreover, we utilized laser irradiation during fabrication route that apart from being rapid and easily scaled up to industrial level also allows for modification of the sample in the specified area of any shape. Base material, i.e. TiO2NTs with deposited Au layers, underwent treatment by means of UV laser (355 nm, 12 ns, 2 Hz, 30-240 mJ/cm2). SEM inspection revealed the formation of Au nanoparticles on the rims of the tubes for mild irradiation conditions while increasing of laser beam energy led to melting of the top layer of the nanotubes. Nevertheless, underneath, the initial architecture of the TiO2NTs remained intact. Structural measurements confirmed the anatase phase of the material and no shift of the main anatase mode peak was observed. The optical studies indicated that laser processing is causing the narrowing of the energy bandgap, which is of key importance for future applications in solar-driven processes. For the optimised, laser-modified 5 nm Au film deposited onto titania nanotubes, the current density registered in dark exceeds 2 mA/cm2, while for the 10 nm Au coating – over 4 mA/cm2 at 1.5 V. When the materials were illuminated by simulated solar light, the current densities reach over 3.5 and almost 6 mA/cm2, respectively. It was also proven that the concentration of donor density increases with the laser fluence, and for TiO2NTs covered with a 10 nm Au layer and irradiated with 240 mJ/cm2 laser fluence, it drastically increases in comparison to the other configurations. This indicates the superior unique effect arising when titania covered by gold film is treated by laser beam under optimised conditions. We strongly believe that Au-TiO2 nanomaterial with boosted photoactivity can find application in water splitting simulated by the Sun, as water photo-assisted decomposition was observed in the studied case.

13:30 - 13:45
3A-I2
Galan-Mascaros, J. R.
Institute of Chemical Research of Catalonia (ICIQ)
Novel Strategies to Enhance OER Electrocatalysis in Alkaline Media
Galan-Mascaros, J. R.
Institute of Chemical Research of Catalonia (ICIQ), ES
Authors
J. R. Galan-Mascaros a, b, Núria López a, Felipe Garcés-Pinedaº a, Huu Chuong Nguyën a, Mabel De Fez-Febré a
Affiliations
a, Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avinguda dels Països Catalans, 16, Tarragona, ES
b, Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain, Passeig Lluis Companys 23, Barcelona, ES
Abstract

The oxygen evolution reaction (OER) is a key process in the general development of sustainable solar fuels, and essential in the progress/growth of an alternative hydrogen economy. This is a very demanding reaction, since a OER catalysts must be fast and efficient, but also stable and robust to high oxidation potentials, water, oxygen, radicals, acids or bases, etc. Several earth abundant metal oxides have appeared as excellent OER electrocatalysts in alkaline conditions, thanks to the robust stability of metal oxides in high pH.1 The most common agreement suggests that FeNi oxo-hydroxides are arguably the best OER catalyst at pH > 13,2 although many other binary and ternary candidates appear close in activity.3 The complexity of this reaction makes difficult to understand and optimize the performance of these catalysts, with the remaining goal to minimize overpotentials, and to maximize current densities. Indeed, after thousands of experiments with multiple phases, the latest progress reports deal with further nanostructuration and smart processing of the materials to increase active surface area.4

In this presentation we will introduce some novel strategies to enhance OER activity in alkaline conditions. On one end, we will demonstrate how the use of magnetic fields may boost the performance of classic magnetic metal oxides.5 On the other end, we will show how a non-redox doping approach opens alternative (and faster) mechanistic pathways.6 Both strategies were developed from the combination of experiment and theory, as an example of the powerful contribution that computational chemistry can bring to the field, opening new alternatives difficult to disclose or understand exclusively from experimental data analysis.

13:45 - 13:55
Discussion
13:55 - 14:10
Break
Session 3B
Chair: Bastian Mei
14:10 - 14:15
3B-O1
Mei, Bastian
Bastian Mei Presentation
Mei, Bastian
Authors
Bastian Mei a
Affiliations
a, Faculty of Science and Technology (TNW), University of Twente
Abstract
14:15 - 14:30
3B-I1
Vermaas, David
Delft University of Technology, The Netherlands
Aqueous electrocatalytic reactors at high current densities
Vermaas, David
Delft University of Technology, The Netherlands, NL
Authors
David Vermaas a
Affiliations
a, Department of Chemical Engineering, Delft University of Technology (TU Delft), The Netherlands, NL
Abstract

Electrocatalytic conversion of water and CO2 into fuels and chemicals has obtained large attention as potential routes for large scale energy storage and renewable feedstock. However, the scaling and intensifying electrocatalytic CO2 conversion faces many challenges. My work targets electrocatalytic reduction processes for upscaled reactors, operation at a typical current density > 200 mA/cm2.

One of the well-known issues at these high current density is the mass transport limitation of e.g. dissolved CO2 in aqueous phase. Gas-phase CO2 conversion has been extensively explored in literature to mitigate the CO2 diffusion limitation. At the same time, electrochemical reduction in vapour phase introduces challenges regarding water management and product cross-over. Therefore, new strategies that can boost the mass transport in water-based electrochemical systems do have potential for large scale CO2 reduction. Moreover, other electrochemical systems, such as flow batteries and membrane technologies, benefit from the same mass transfer enhancement in water-based systems. For enhancing mass transfer in aqueous electrochemical systems, gas bubbles play a central role. For many processes, gas bubbles decelerate the process via electrical resistance and shielding catalytic area. However, when controlling the gas bubble movements, we can leverage the convective properties of gas bubbles to improve the mass transfer. In this talk, I will highlight the perspectives for CO2 reduction in gas phase, but also possibilities for CO2 reduction at high current density in aqueous phase.

14:30 - 14:40
3B-T1
García-Tecedor, Miguel
Universitat Jaume I, Institute of Advanced Materials (INAM) - Spain
Solution-processed Nickel Oxide electrocatalyst for Electrochemical Water Splitting
García-Tecedor, Miguel
Universitat Jaume I, Institute of Advanced Materials (INAM) - Spain, ES
Authors
Miguel García-Tecedor a, Sixto Giménez a, Jaume Noguera b, Rafael Abargues b
Affiliations
a, Universitat Jaume I, Institute of Advanced Materials (INAM) - Spain, Avinguda de Vicent Sos Baynat, Castelló de la Plana, ES
b, UMDO, Instituto de Ciencia de los Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Abstract

The development of sustainable, fossil-free strategies to synthesize fuels and added-value chemicals has raised enormous interest in the last years, in order to provide reliable energy vectors as well as the feedstocks needed for the chemical industry at a global scale. In this context, water oxidation stands out as one of the preferred reaction to provide the protons and electrons needed for electrochemical conversion processes, although this reaction is considered a kinetic bottleneck and consequently, the development of electrocatalytic materials that effectively oxidize water is essential for improving the efficiency of the overall electrochemical conversion process. Currently, the most efficient water oxidation catalysts (WOC) are based on iridium and ruthenium oxides, IrO2 and RuO2. However, due to the scarcity and high-costs of these precious metal-based oxides, other alternatives need to be explored. Ni-based materials constitute one of the best alternatives due to their high electrocatalytic activity and stability under alkaline conditions, as a consequence of their high electrical conductivity and corrosion resistance. Indeed, large scale commercial Liquid Alkaline (LA) electrolyzers, preferentially use nickel-based anodes. Herein, an “Earth-abundant” undoped Nickel oxide (NiOx) electrocatalyst for water oxidation was investigated. An up-scalable and low-cost solution-based sol-gel synthetic route was employed to obtain non-stoichiometric NiOx electrocatalyst baked at mild temperatures from 100 to 500 ºC. The catalytic activity towards water oxidation was found to be inversely proportional to the baking temperature. The defective and amorphous nature of the NiOx electrocatalysts baked at the lowest temperatures (< 200 ºC) was assessed by a wide range of different structural, optical and spectroscopic techniques, leading to a higher acceptor density, attributed to a higher density of structural/electronic defects. Our champion NiOx catalyst grants 358 mV of overpotential at 10 mA cm-2 and more than 60h of continuous operation without significant losses.

14:40 - 14:55
3B-I2
Endrődi, Balázs
University of Szeged
Development of Zero-gap CO2 Electrolyzers: Prospects and Bottlenecks for Industrial Implementation
Endrődi, Balázs
University of Szeged, HU
Authors
Balázs Endrődi a, Egon Kecsenovity a, Angelika Samu a, Tibor Halmágyi a, Csaba Janáky a
Affiliations
a, University of Szeged, HU
Abstract

Electrochemical reduction of CO2 offers to decrease the atmospheric emission of a greenhouse gas, meanwhile producing valuable chemicals – hence closing the “artificial carbon-cycle”. One of these potential products is CO, which combined with H2 could (partly) replace the fossil fuel based organic synthesis methods, and could be a precursor for the formation of a large variety of chemicals including dimethyl ether or specialty wax.

We present a zero gap electrolyzer cell for the continuous-flow electrochemical reduction of CO2, and its possible scale-up avenues in terms of lateral size increase and the construction of multi-layer electrolyzer stacks.[1] Notably, all these structural changes involve the fine-tuning of the operation conditions, achieved by using a custom-designed, almost fully automatized test station. Using commercially available silver catalyst in a gas diffusion electrode configuration we show the selective formation of CO (with H2 being the only cathodic by-product) with similar efficiency metrics in the different sized electrolyzer cells. Further, employing a poly(aryl piperidinium)-based anion exchange membrane (PiperION) with high carbonate conductance in conjunction with a tailored electrolyzer cell structure, we present high partial current densities for CO production, while maintaining high conversion, selectivity at a reasonable cell voltage.[2]

14:55 - 15:10
Discussion
15:10 - 15:20
3B-T2
Kas, Recep
The Influence of Along-the-Channel Gradients on Spatioactivitiy and Spatioselectivity of Gas Diffusion Electrodes during Electrochemical CO2 Reduction
Kas, Recep
Authors
Recep Kas a, b, Andrew G. Star b, Kailun Yang c, Tim Van Cleve b, K.C. Neyerlin b, Wilson A. Smith a, b, c
Affiliations
a, University of Colorado Boulder, US
b, National Renewable Energy Laboratory, Golden, Colorado, 1617 Cole Boulevard, Golden, Colorado, 80401, US
c, Delft Technical University, Julianalaan 136, Delft, 2628, NL
Abstract

Microfluidic and polymer electrolyte membrane (PEM) reactor designs with different configurations were used for studying electrochemical CO2 reduction at room temperature, each having particular advantages. PEM based reactors with zero-gap configuration containing a membrane electrode assembly (MEA) might offer several advantages over other device architectures such as having lower ohmic drops at high current density, higher volumetric energy density, making them more suitable to scale-up.1,2 However, PEM based and microfluidic reactors with flowing liquid catholyte are the most numerous configuration in electrochemical CO2 reduction so far.3,4 The studies in gas-fed electrochemical cells with flowing liquid catholyte provided crucial information on the effect of process conditions and material parameters to the selectivity and activity of the electrocatalytic process. Although this configuration might suffer from huge ohmic loses at high current density and require more technical control for scaling up ,from both a fundamental and applied perspective, it is important understand the effect of mass transport and process conditions on the performance and catalyst screening in these systems.

We will present results of a 2-D transport model for a gas diffusion electrode performing CO2 reduction to CO with a flowing catholyte, including the concentration gradients along the flow cell, spatial distribution of the current density and local pH in the catalyst layer. The model predicts that both the concentration of CO2 and the buffer electrolyte gradually diminish along the channel for a parallel flow of gas and electrolyte as a result of electrochemical conversion and non-electrochemical consumption. The effect of concentration gradients along the flow channel on the current density distribution becomes prominent at high conversions (e.g. current density) when compared to the ohmic drops across the electrochemical cell (Figure 1a), and a strong variation of the electrochemical performance is observed along the flow path (Figure 1b). In addition, the contribution of concentration overpotentials to overall potential losses dramatically changes with the CO2 gas inlet feed flow rate, which results in differences in outlet concentrations at high conversions. Fundamental and practical implications of our findings to electrochemical CO2 reduction are discussed particularly at high single-pass conversions.

15:20 - 15:30
3B-T3
Valls Mascaró, Francesc
Leiden University
Improving the Platinum Stability for Fuel Cell Operation
Valls Mascaró, Francesc
Leiden University, NL
Authors
Francesc Valls Mascaró a, Marc T.M. Koper a, Marcel J. Rost b
Affiliations
a, Leiden University, Leiden Institute of Chemistry, Leiden, 2300, NL
b, Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, NL
Abstract

The longevity of catalysts is crucial for making industrial scale applications economically feasible. The high activity of platinum favors its applications in electrochemical energy conversion systems, although platinum clearly suffers from degradation during fuel cell operation. The degradation is caused by the nucleation and growth of nanoislands, which undesirably roughens the surface [1, 2, 3, 4]. It has been shown that the extent of this roughening can be tuned by including additives, varying the pH of the electrolyte, or by applying different potential windows [5, 6, 7].
Considering fundamental surface science background knowledge, in particular, adatom density, Gibbs-Thomson pressures, and critical nuclei sizes, we set out to explore the roughness evolution on Pt(111)-like surfaces with different step densities. Intending to decrease the roughness evolution, we show that it is possible to smartly tune the step density with respect to the growth speed: this results in a significantly decreased interface width (roughness) and, when pushing the limits, to an even completely flat single crystalline surface exhibiting only the preexisting steps without any additional roughness build-up.

 

15:30 - 15:50
3B-K1
Seger, Brian
Technical University of Denmark (DTU)
Understanding the Carbon Balance and pH effects in CO2 Electrolysis Devices
Seger, Brian
Technical University of Denmark (DTU), DK
Authors
Brian Seger a, Ming Ma a, Gaston Larrazabal a
Affiliations
a, Technical University of Denmark, Department of Physics, Fysikvej, 312, Kongens Lyngby, DK
Abstract

CO2 emissions are significantly contributing to anthropogenic climate change, but at the same time the costs of sustainably based electricity has greatly been reduced in the last decade.  This has provided a perfect economic and societal opportunity for electrochemical CO2 reduction into chemicals. However, this field is not technologically mature yet, and there are many engineering details that needs to be investigated.  This talk will focus on understanding the complete carbon balance on low temperature electrochemical CO2 reduction reactors operating at industrial relevant current densities (100-500 mA/cm2). The focus will be primarily be on using a gas diffusion approach with a liquid catholyte using sputtered Cu as a catalyst.

By employing a post-reactor volumetric flow rate to measure outlet flow rates, highly accurate faradaic efficiency measurements were achieved. Furthermore, these results show that if one instead assumes inlet gas flowrates, this can overestimate faradaic efficiencies of gas products by up to 25%. By careful analysis of both gas and liquid products we show a near 100% faradaic efficiency as well as completely accounting for all the carbon in our reactor.  Our liquid analysis showed glycoaldehyde and ethylene glycol, two products never seen before in high current density electrochemical CO2 reduction reactors

Using an anion exchange membrane, we show significant crossover to the anode of anionic species such as acetate, and formate, as well as carbonate crossover and subsequent CO2 evolution on the anode.  We show that the ratio of CO2 to oxygen evolution on the anode is 2:1 throughout a current density range of 100-300 mA/cm2, however the time it takes to equilibrate at this ratio is both current dependent and dependent upon the catholyte and anolyte reservoirs.  This talk will also discuss variations in pH at both the anode and cathode as a function of operating parameters and give insight into the potential advantages and pitfalls of various reactor designs.

15:50 - 16:00
Discussion
16:00 - 16:05
Closing
 
Posters
Katarzyna Siuzdak, Jakub Wawrzyniak, Łukasz Haryński, Katarzyna Grochowska
Laser tailoring of the hierarchical titania towards ultrafast and scalable surface modification of photoelectrode materials
Arthur Shih, Nakkiran Arulmozhi, Marc Koper
Electrocatalysis Under Cover: Enhanced HER via Defective Graphene Covered Pt(111)
Camilo A. Mesa, James R. Durrant, Sixto Gimenez
Spectroelectrochemical analysis of the water oxidation mechanisms on metal oxide electrocatalysts
Margot Olde Nordkamp
In situ ATR-SEIRAS Study on Kolbe Oxidation of Acetic Acid on a Platinum Electrode
Piyush Chauhan, Karl Hiekel, Justus S. Diercks, Viktoriia Saveleva, Juan Herranz, Alexander Eychmüller, Thomas J. Schmidt
Electrochemical Studies of Gold Aerogels and Commercial Gold-based Catalysts for CO2 Electroreduction
Kevinjeorjios Pellumbi, Mathias Smialkowski, Daniel Siegmund, Ulf-Peter Apfel
Effect of the S/Se Exchange on the HER and CO2RR Activity of Fe/NI-Pentlandites
Kevin Van Daele, Nick Daems, Daniel Choukroun, Deepak Pant, Tom Breugelmans
Carbon-supported Cu/SnO2 Core-shell Nanoparticles for the Selective Electrochemical CO2 Reduction Towards Formic Acid
Sixto Gimenez, Roser Fernandez-Climent, Miguel Garcia-Tecedor
Copper Derived Catalysts for Electrochemical CO2 Reduction Reaction
Oriol Gutiérrez, Nick Daems, Willem Offermans, Yuvraj Y. Birdja, Metin Bulut, Deepak Pant, Tom Breugelmans
Electrochemical Conversion of Bicarbonate to Formate Promoted by the Inhibition of the Hydrogen Evolution Reaction
Bert De Mot, Jonas Hereijgers, Nick Daems, Tom Breugelmans
Formate Production in Zero‐Gap Carbon Dioxide Electrolyzers
Hongyu An, Longfei Wu, Laurens M. D B. Mandemaker, Shuang Yang, Jim de Ruyter, Jochem H. J. Wijten, Joris C. L. Janssens, Ward van der Stam, Bert M. Weckhuysen
In-Situ Sub-second Time-resolved Surface Enhanced Raman Spectroscopy (TR-SERS) Reveals Dynamic C-C Coupling Intermediates during Electrochemical CO2 Reduction on Copper
Katherine Villa, Sebastián Murcia-López, Joan R. Morante, Teresa Andreu
Selective oxidation of methane to methanol over a mesoporous WO3 photocatalyst
Shuang Yang, Hongyu An, Jochem Wijten, Longfei Wu, Wenjie Xu, Dimitra Anastasiadou, Ward van der Stam, Bert M. Weckhuysen
Waste-derived Bimetallic Cu/Pb Nano-particles for Effectively Selective Formation of C1 Products in CO2 Electroreduction
Jim de Ruiter, Hongyu An, Ward van der Stam, Bert Weckhuysen
Time Resolved Raman Study on Surface Species during Cyclic Voltammetry on Copper Electrodes
Rose Oates, Carys Hor, Xuyang Chen, James Murawski, Daniel Webber, Stefano Mezzavilla, Mehtap Oezaslan, Milo S P Shaffer, Ifan E L Stephens
Inhibition of the Parasitic Hydrogen Evolution Reaction on Commercial Carbon Black Materials
Ainoa Paradelo Rodríguez, Bastian Mei, Guido Mul
Ethanol electrooxidation mechanism: Operando Electrochemistry – Mass Spectrometry Study
Domenico Grammatico, Huan Ngoc Tran, Yun Li, Silvia Pugliese, Laurent Billon, Bao-Lian Su, Marc Fontecave
Immobilization of a Molecular Re Complex on MOF-Derived Hierarchical Porous Carbon for CO2 Electroreduction in Water/Ionic Liquid Electrolyte
Phil Calado, Ilario Gelmetti, Piers Barnes
Driftfusion: An Open Source Code for Simulating Ordered Semiconductor Devices with Mixed Ionic-Electronic Conducting Materials in One-Dimension
Laura Mallón, Nuria Romero, Alicia Jiménez, Elena Martín Morales, José Alemán, Rubén Mas-Ballesté, Roger Bofill, Karine Philippot, Jordi García-Antón, Xavier Sala
The Role of Catalyst–Support Interactions in Oxygen Evolution Anodes Based on Co(OH)2 Nanoparticles and Carbon Microfibers
Qianqian Song, Marta Costa Figueiredo, Junqi Li
Sulfur Modified Cobalt-Copper Hydroxide Nanorods Array for Enhanced Oxygen Evolution Reaction
Xiangkun (Elvis) Cao, Xu Liu
Self-doping of Nanostructured TiO2 for Enhanced Photoelectrocatalytic Performance
Yue Zhang, Lu Gao, Jan Philipp Hofmann, Marta Figueiredo, Emiel Hensen
CO2 Electrochemical Reduction on Oxide-Derived Cu: Oxidation States vs. Surface Roughness
Kirankumar Kuruvinashetti, Nikolay Kornienko
Linker modulated peroxide electrosynthesis using metal-organic nanosheets
Tim Wissink, Marta Figueiredo, Emiel Hensen
Effect of doping In2O3 with transition metals on the electrocatalytic reduction of CO2 to formate
Felipe Andrés Garcés-Pineda, Huu Chuong Nguyën, Marta Blasco-Ahicart, Miguel García-Tecedor, Mabel de Fez Febré, Peng-Yi Tang, Jordi Arbiol, Sixto Giménez, José Ramón Galán-Mascarós, Núria López
Electrocatalytic water oxidation activity of NiZnFe spinels in basic media
Marina Peña-Díaz, Weronica Linpé, Gary S. Harlow, Edvin Lundgre, Celia Rogero, Sara Barja
Potential induced structure changes at Au(111) surface in acidic solution
Yuxuan Zhang, Nikolay Kornienko
Metal-organic framework with molecularly defined active sites as a model system for electrochemical biomass valorization
Dimitra Anastasiadou, Jasmijn T.D. Janssen, Emiel Hensen, Marta Costa Figueiredo
Study of Cu-Rh electrodes for nitrate electrochemical reduction

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