Cation effects on electrocatalytic reduction processes at the example of the hydrogen evolution reaction

Cation effects provide invaluable insights into electrochemistry. In this review, I discuss them with a main focus on the hydrogen evolution reaction and a summary of recent in situ spectroscopic and electrochemical measurements as well as advanced computational simulation results conducted at varying cation identities, concentrations, and pH. According to these works, the interfacial cation concentration is the main descriptor to explain cation and pH effects. The detailed mechanism (such as e.g. water polarization, water structure changes, field-stabilization of intermediates) depends strongly on potential, pH, oxophilicity of the electrode, or the nature of the rate-limiting step and proton donor. With growing conver-gence in this field, cation effects remain a highly challenging and promising topic for research.

Automated summary

Cation effects play a crucial role in understanding electrochemistry. This review focuses on the hydrogen evolution reaction, discussing recent experimental and computational studies conducted with different cation identities, concentrations, and pH values. It is found that the interfacial cation concentration is the key factor in explaining cation and pH effects. The detailed mechanism depends on factors such as electrode properties, potential, pH, and proton donation. Overall, cation effects present a challenging and promising area for further research.