Constructing Co-S interface chemical bonds over Co@NC/ZnInS for an efficient solar-driven photocatalytic H evolution.

Developing novel photocatalysts with an intimate interface and sufficient contact is significant for the separation and migration of photogenerated carriers. In this work, a novel Co@NC/ZnInS heterojunction with a strong Co-S chemical bond was formed at the interface between Co@NC and ZnInS, which accelerated charge separation. Meanwhile, the recombination of the electron-hole pairs was further restricted by the Co@NC/ZnInS Schottky junction. The Co@NC (5 wt%)/ZnInS composite exhibited an H evolution rate of 33.3 μmol h, which is 6.1 times higher than that of the pristine ZnInS, and Co@NC/ZnInS showed excellent stability in the photocatalytic water splitting reaction. Its apparent quantum yield reached 38% at 420 nm. Furthermore, the Kelvin probe test results showed that the interfacial electric field formed as the driving force for interface charge transfer was oriented from Co@NC to ZnInS. In addition, the Co-S bond as a high-speed channel facilitated the interfacial electron transfer. This work reveals that formed chemical bonds will pave the way for designing high-efficiency heterojunction photocatalysts.