Constructing Co-S interface chemical bonds over Co@NC/ZnIn 2 S 4 for an efficient solar-driven photocatalytic H 2 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/ZnIn 2 S 4 heterojunction with a strong Co-S chemical bond was formed at the interface between Co@NC and ZnIn 2 S 4 , which accelerated charge separation. Meanwhile, the recombination of the electron-hole pairs was further restricted by the Co@NC/ZnIn 2 S 4 Schottky junction. The Co@NC (5 wt%)/ZnIn 2 S 4 composite exhibited an H 2 evolution rate of 33.3 μmol h -1 , which is 6.1 times higher than that of the pristine ZnIn 2 S 4 , and Co@NC/ZnIn 2 S 4 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 ZnIn 2 S 4 . In addition, the Co-S bond as a high-speed channel facilitated the interfacial electron transfer. This work reveals that in situ formed chemical bonds will pave the way for designing high-efficiency heterojunction photocatalysts.