Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 58: Solid-Liquid Interfaces: Reactions and Electrochemistry II

O 58.5: Talk

Wednesday, March 19, 2025, 11:30–11:45, H4

Microkinetic Modeling of the Hydrogen Evolution Reaction in Alkaline Conditions — •Dipam Patel and Georg Kastlunger — Technical University of Denmark

The Hydrogen Evolution Reaction (HER) in alkaline media is distinguished from the acidic case by the source of H. Significant theoretical work has investigated and diagnosed activity in acidic conditions, but this understanding does not necessarily correspond to alkaline. The implications of the stronger O-H bond in H2O compared to that in H3O+ are not yet fully understood. Using constant-potential electrochemical barriers, we developed a microkinetic model of alkaline HER activity on a selection of close-packed metallic surfaces. By accounting for the different potential responses of catalysts, we are able to reproduce the relative rates and tafel slopes seen in experiment. By relating the calculated activities to electrochemical descriptors, we show that the application of solely hydrogen binding descriptors, as in acidic HER, does not fully explain HER activity in alkaline.

Keywords: Microkinetic Modeling; Constant-Potential Kinetics; Electrocatalysis