Facile construction of a sulfur vacancy defect-decorated CoS@InS core/shell heterojunction for efficient visible-light-driven photocatalytic hydrogen evolution.

Photoinduced electron-separation and -transport processes are two independent crucial factors for determining the efficiency of photocatalytic hydrogen production. Herein, a sulfur vacancy defect-decorated CoS@InS (CoS@V-InS) core/shell heterojunction photocatalyst was synthesized an sulfidation method followed by a liquid-phase corrosion process. Photocatalytic hydrogen evolution experiments showed that the CoS@V-InS nanohybrids delivered an attractive photocatalytic activity of 4.136 mmol h g under visible-light irradiation, which was 8.23 times higher than that of the pristine InS samples. As expected, V could enhance the charge-separation efficiency of InS through rearranging the electrons of the InS basal plane, in addition to improving the electron-transfer efficiency, as visually verified by transient absorption spectroscopy. Mechanism studies based on density functional theory calculations confirmed that the In atoms adjacent to V played a key role in the translation, rotation, and transformation of electrons for water reduction. This scalable strategy focused on defect engineering paves a new avenue for the design and assembly of 2D core/shell heterostructures for efficient and robust water-splitting photocatalysts.