Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 97: Solid-liquid interfaces: Reactions and electrochemistry III

O 97.11: Talk

Friday, March 13, 2026, 12:15–12:30, TRE/PHYS

Entropy-Enthalpy Relationships in Heterogeneous Electrocatalysis: A Case Study of the Hydrogen Evolution Reaction — •Andrew J. Wong, Barbara Sumić, Elias Diesen, Nicolas G. Hörmann, Hendrik H. Heenen, Karsten Reuter, and Vanessa J. Bukas — Fritz-Haber-Institut der MPG, Berlin

Temperature is a key parameter in industrial electrolyzers. And yet, the vast majority of mechanistic lab-scale studies ignores temperature variations by operating at room temperature. This is surprising since existing experimental evidence has shown that even modest heating can significantly affect the rate and selectivity of electrocatalytic reactions. Understanding the origin of such effects is crucial for advancing fundamental electrocatalysis and exploiting temperature as a control parameter. Here, we explore temperature effects on the hydrogen evolution reaction (HER) by developing a simple mean-field microkinetic model based on first-principles energetics. An Arrhenius analysis on the HER rates across different metal catalysts reveals distinct entropy-enthalpy correlations, reflected in the apparent activation enthalpy and entropy-dependent prefactor. Despite the simplicity of our model, these trends are in remarkable qualitative agreement with experiments. A degree of rate control analysis explains the kinetic fingerprints in terms of a change in the rate-determining step, inducing a shift in kinetic regime. We thus conclude that the enthalpy-entropy compensation effect is explained, at least to a first approximation, by the surface kinetics. Our work overall highlights the subtle interplay between temperature, applied potential, and catalyst reactivity.

Keywords: electrocatalysis; temperature; microkinetic model; hydrogen evolution reaction; compensation effect