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 (001) and (110) CBTS surfaces. Our study suggests that amongst the different surfaces considered in this work, the metal-rich (110) 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.