The role of lone-pair electrons on electrocatalytic activity of copper antimony sulfide nanostructures

Crystal engineering is an elegant approach to the synthesis and design of active electrocatalysts for the large-scale production of hydrogen. Better realization of the crystal structure of the electrocatalyst assists the development of active catalysts. Different properties such as thermal properties, optical properties etc., appear to be largely affected by the presence of nonbonding lone-pair in the crystal structure. In this work, we have studied the influence of nonbonding electron pairs residing in the crystal structure on the electrocatalytic activity of the electrocatalysts. Herein, we report the synthesis of the three distinct crystal phases of copper antimony sulfide nanostructures named chalcostibite (CuSbS2), skinnerite (Cu3SbS3), and famatinite (Cu3SbS4), and studied their electrocatalytic activity in neutral medium. Chalcostibite and skinnerite phase show much better activity towards electrocatalytic hydrogen evolution reaction than the famatinite phase. This is explained due to the presence of antimony (Sb) lone pair electron in the former two cases compared to the latter.