How Metal/Insulator Interfaces Enable the Enhancement of the Hydrogen Evolution Reaction Kinetics in Two Ways

TL;DR

This paper uncovers a novel mechanism at metal/insulator interfaces that significantly enhances hydrogen evolution reaction kinetics by facilitating hydrogen adsorption and ion transfer, supported by experimental and simulation data.

Contribution

It reveals a new mechanism at metal/insulator interfaces that improves HER kinetics, guiding the design of advanced electrocatalytic systems.

Findings

Enhanced HER due to metal/insulator interface effects

Mechanism supported by electrochemical and simulation data

Design principles for improved electrocatalysts derived

Abstract

Laterally nanostructured surfaces give rise to a new dimension of understanding and improving electrochemical reactions. In this study, we present a peculiar mechanism appearing at a metal/insulator interface, which can significantly enhance the Hydrogen Evolution Reaction (HER) from water reduction by altering the local reaction conditions in two ways: facilitated adsorption of hydrogen on the metal catalyst surface and improved transfer of ions through the double layer. The mechanism is uncovered using electrodes consisting of well-defined nanometer-sized metal arrays (Au, Cu, Pt) embedded in an insulator layer (silicon nitride), varying various parameters of both the electrode (size of the metal patches, catalyst material) and the electrolyte (cationic species, cation concentration, pH). In addition, simulations of the electrochemical double layer are carried out, which support the elaborated mechanism. Knowledge of this mechanism will enable new design principles for novel composite electrocatalytic systems.