Mechanistic insights of hydrogen evolution reaction on quaternary earth-abundant chalcogenide Cu2BaSnS4 from first principles

Abstract

Photocatalytic conversion of water to produce hydrogen is an environment-friendly way of converting solar energy to chemical energy. In the last two decades, the quaternary chalcogenide family of semiconductors has become a potentially important class of materials for this purpose. Amongst them, earth-abundant and non-toxic Cu2BaSnS4 (CBTS) is emerging as a promising candidate for photocathode where the Hydrogen evolution reaction (HER) takes place. In this work, using first-principles density functional theory-based calculations, we have provided mechanistic insights into (photo-)electrochemical HER on low-indexed (0 0 1) and (1 1 0) CBTS surfaces. Our study suggests that amongst the different surfaces considered in this work, the metal-rich (1 1 0) termination might be the most efficient one for HER reaction. We believe our result will be beneficial for the future development of HER photocathodes employing this group of materials.