An In situ Raman study of intermediate adsorption engineering by high-index facet control during the hydrogen evolution reaction

Electrocatalytic reduction of water is a promising route to produce hydrogen under mild conditions. High-index facet control is one of the most promising ways to achieve excellent catalytic activity for the hydrogen evolution reaction (HER). However, the mechanism of the high-index facet enhancement remains unclear. Here, we combine in situ Raman spectroscopy and theoretical calculations to elucidate the mechanism of HER catalytic performance enhanced by high-index facets on Ti@TiO2 nanosheets. During the HER process, water molecules tend to adsorb to the high-index facet surface and then reduce to hydrogen. Our work lays the foundation for future exploration of the mechanism of electrocatalysis in transition-metal-based electrocatalysts by in situ Raman spectroscopy for applications in energy and environment-related issues.