Ruthenium-Rhenium and Ruthenium-Palladium Supramolecular Photocatalysts for Photoelectrocatalytic CO2 and H+ Reduction
Joshua Karlsson a, Elizabeth Gibson a, Mary Pryce b
a School of Natural and Environmental Sciences, Newcastle University, UK, Newcastle upon Tyne, Reino Unido, Newcastle upon Tyne, United Kingdom
b School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
International Conference on Hybrid and Organic Photovoltaics
Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
València, Spain, 2022 May 19th - 25th
Organizers: Pablo Docampo, Eva Unger and Elizabeth Gibson
Poster, Joshua Karlsson, 214
Publication date: 20th April 2022

Photoelectrocatalysis (PEC) is a promising means of generating solar fuels without the need for unsustainable sacrificial electron sources[1], such as oft-used tertiary aliphatic amines. Decades of research into photocatalytic systems for artificial photosynthesis has produced few candidates for molecular systems capable of overall water-splitting or CO2 reduction. An alternative strategy involves decorating semiconductor surfaces with suitable photocatalysts to create a photoanode in a photoelectrochemical system. Thus we can facilitate the half-reactions of water-splitting or CO2 reduction by applying an external bias, which itself can come from a solar cell. Using molecular photocatalysts in a PEC cell allows for a great amount of control over the reaction conditions, electrode and chromophore. Furthermore, it has been demonstrated that the excited state dynamics of photocatalysts are greatly perturbed by electric fields present on the semiconductor surface, in operando.[2]

In the current study we introduce two molecular photocatalysts designed for H+ and CO2 reduction on a semiconductor surface. These chromophores adsorb to a semiconductor, NiO in this case, by means of a carboxylic acid anchoring group. The molecular dyads contained a rhenium carbonyl or palladium-based catalytic centre bridged to a ruthenium bipyridyl photosensitizer.[3] The photocathodes were evaluated for photoelectrochemical reduction of CO2 to CO or H+ to H2 and the performances were compared directly with a control compound lacking the catalytic site. A suite of electrochemical, UV-visible steady-state/time-resolved spectroscopy, X-ray photoelectron spectroscopy and gas chromatography measurements were employed to gain kinetic and mechanistic insight into primary electron transfer processes and relate the structure to the photoelectrocatalytic performance under various conditions in aqueous media.

Joshua Karlsson and Elizabeth Gibson thank Newcastle University, the Engineering and Sciences Research Council (EPSRC) and the North East Centre for Energy Materials EP/R021503/1 for funding. Mary T. Pryce thanks the Irish Research Council for funding.

We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info