Improving stability of iridium oxide based anodes for water electrolysis

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Polymer electrolyte membrane water electrolysers (PEMWE) represent many advantages over conventional alkaline electrolysers including the ability to operate at high current density as well as being able to better cope with intermittent use that would accompany the use of renewable energy sources such as wind and solar power. While much work has been conducted on reducing or removing the noble metal content for the catalysis of the sluggish oxygen evolution reaction (OER) that occurs at the anode in PEMWE, the anode catalyst (IrOx/RuOx) represents a small percentage (3.6%) of the total cost of a PEMWE system. Therefore, to improve the commercial viability of PEM electrolysers improvements to stack lifetime are required. One of the principles ways this could be achieved is to increase the stability of the catalysts used.This project will look at improving the understanding of OER catalysts stability and dissolution mechanism as well as build on methods for standardised short term accelerated testing in aqueous acidic media that can better benchmark stability of OER catalysts for PEMWE applications. The intention is also to conduct a comparison of results obtained in three electrode laboratory testing to in-operando (MEA testing) using thermally prepared rutile IrO2 catalysts which have previously shown to be the most stable for OER. In addition, it will look at ways to improve stability of catalysts while retaining their activity such as work previously conducted on the use of mixed oxides and metal addition to specific surface sites.Throughout the project particular effort will be made to try and associate electrochemical data to surface descriptors to better determine which physical features of the nanoparticles affect metal dissolution. This information should enable better development of electrochemical catalysts that suffer less from metal dissolution when in operation at high potentials such as those required for electrochemical water splitting for hydrogen fuel generation