Publication date: 21st July 2025
Oxygen evolution reaction (OER) is the rate limiting step in (photo)electrochemical solar fuels production processes in aqueous medium like water splitting or CO2 reduction. This is because the oxidation of water is energetically demanding (1.23 V vs RHE at pH = 0 and 25 oC) and slow, with sluggish kinetics and a complex, multistep mechanism that involves 4 electrons. Noble metal oxides are typically employed as electrocatalysts, such as RuOx or IrO2, but these are scarce and expensive. [1] Therefore, cheaper, more accessible alternatives are required to escalate (photo)electrocatalytic solar fuels production. In this context, photoelectrocatalysts based on transition metal-oxides are thoroughly investigate due to their ability to harness sunlight to yield chemical reactions, their low cost and their accessibility.
Among them, bismuth vanadate (BiVO4) stands out due to its: a) n-type character, b) narrow band gap (2.4 eV), c) suitable valence band (VB) position, d) non-toxicity, and e) low cost. However, this material also suffers from certain drawbacks, namely, slow carriers’ transportation and surface recombination that ultimately lead to slow OER kinetics and photocorrosion. [2]
Many approaches are being studied to tackle these inconveniences like different preparation methods, nanostructuring, heterojunctions, or usage of cocatalysts. In this work, we explore two of these strategies: i) inorganic-organic heterojunctions between BiVO4 and a conjugated porous polymer (CPP) based on 1,3,5-tri(thiophen-2-yl)benzene (3TB) monomer; and ii) deposition of MOOH (M = Fe, Ni, Fe+Ni) cocatalysts over BiVO4 films.
The BiVO4 films were prepared over FTO substrates through electrodeposition followed by organometallic thermal decomposition. Then, a 3TB-based CPP was deposited with different thicknesses onto the BiVO4 films by cyclic voltammetry (CV) and its presence was confirmed by energy-dispersive X-ray spectroscopy (EDX). The hybrid photoelectrodes were then characterized photoelectrochemically by linear sweep voltammetry (LSV) and chronoamperometry (CA) under chopped illumination. An enhancement in stability could be observed (Figure a).
In another set of BiVO4 films, MOOH cocatalysts were deposited photo(electro)chemically on top of the films. The presence of the cocatalysts was confirmed by EDX and the morphology of the clusters was studied by field-emission sweep electronic microscopy (FE-SEM). Then, the devices were photoelectrochemically characterized by LSV under chopped illumination -where an improvement in photocurrent, fill factor, and photocurrent onset potential could be observed (Figure b)- and by electrochemical impedance spectroscopy (EIS) under dark and illumination conditions, that revealed a reduction in charge transfer resistance for all the cocatalyst-containing photoelectrodes.
Next steps will be focused on merging both strategies to build an FTO/BiVO4/3TB/MOOH device, optimizing the preparation conditions, and characterize its properties.
This research has been funded with PIPF-2023/ECO-31189 fellowship granted by Comunidad de Madrid.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.