Influence of dynamic operation conditions on the electrolytic hydrogen evolution

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Hydrogen plays a key-role for the conversion and storage of renewable energy. As energy carrier it can either be converted in low-temperature fuel cells to electricity or chemically converted into higher-valued organic molecules. In principle, hydrogen can be obtained by electrolytic water splitting, where one of the main problems is related to the continuous and homogeneous supply of electricity by photovoltaic or wind parks. Therefore, in order to realize a hydrogen economy based on renewable energy, the development of water electrocatalyst that operate efficient, stable and economically under rather fluctuating operation conditions is indispensable. This requires an electrolytic water splitting under acidic conditions, with the flexibility of operation at higher overpotentials without losing long-term stability in particular of the anode materials. Within this joint project of Prof. Jacob (Ulm) and Prof. Over (Gießen) we will investigate the increased corrosion and the activity of Ir-based single-crystalline model oxide-electrodes during acidic oxygen evolution on the microscopic scale, with particular focus on resolving the influence of strongly varying operation conditions. In order to achieve this ambitious goal a tight connection between ab initio theory and experiment will provide a microkinetic description of the occurring electrochemical processes, which will be validated against corresponding operando measurements, with particular emphasis on stability and activity of the electrocatalysts.