Electrochemical catalyst-support interactions (CSI) of oxide-supported oxygen evolution reaction (OER) catalysts and their impact on catalyst activity and corrosion stability

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Electrocatalysts supported on conductive high surface-area carrier materials constitute an important electrode component of electrochemical galvanic and electrolytic cell devices, such as electrolyzers or hydrogen fuel cells. The reactivity and stability of such catalyst/support couples determine the important overall performance metrics, such as cell efficiency and durability. Owing to a direct chemical interaction at their interface, catalyst and support may influence each other’s chemical reactivity, something well known in gas-solid catalysis and, there, commonly referred to as catalyst-support interaction (CSI) or more specifically, as „strong metal-support interactions (smsi)“. The concept of CSI at electrochemical solid-liquid interfaces, however, has largely remained unaddressed, yet is attracting much recent interest due to its potential to enhance both catalytic activity and electrochemical stability of electrocatalysts. This project is designed to address fundamental scientific aspects of electrochemical CSIs at solid-liquid interfaces and explore the possibility to leverage CSIs in real electrocatalyst/support couples. Its major objective is to explore, substantiate, and quantify the chemical nature, the mechanistic origin and measurable impact of CSIs on reactivity and stability in oxide-supported Ir-based oxygen evolution (OER) electrocatalysts. Our working hypothesis is that CSIs can be tailored and leveraged to mitigate catalyst corrosion and degradation during electrolyzer operation. Using well-defined, smooth catalyst/support models, we will explore and compare a selected number of different conductive oxidic support materials and study their impact on the electronic and geometric structure as well as surface redox chemistry and catalytic OER performance of Ir-oxide catalysts with special emphasis on catalyst/support stability. A wide variety of ex-situ and operando characterization techniques, including XAS, XPS, ICP-MS, DEMS, of well-defined surfaces and nanostructures will be employed in the course of this project. Insight in electrochemical CSIs will be transferred to nanostructured Ir based catalyst/support couples operating under catalytic OER conditions. The project team comprises three academic groups with much expertise in electrocatalysis, corrosion science and surface nanocatalysis in combination with operando spectroscopy. As a major outcome, this project will establish a deeper understanding of CSI effect in OER and its insights will aid to include CSI effect in the rational design of water splitting electrocatalysts.