In-situ exsolved NiS nanoparticle-socketed CdS with strongly coupled interfaces as a superior visible-light-driven photocatalyst for hydrogen evolution

Herein, a NiS nanoparticle-socketed CdS photocatalyst (NiS/CdS-e) is developed by hydrothermal sulfurization of Ni-doped Cd(OH)2 precursor, where the Cd(OH)2 particles are converted into CdS while the doped Ni species are exsolved and socketed on the surfaces of CdS. 2% NiS/CdS-e presents a high H2 evolution rate of 18.9 mmol g−1 h−1 with an apparent quantum efficiency (AQE) of 13.9% at 420 nm, much superior to those of pristine CdS (0.5 mmol g−1 h−1) and 2% NiS/CdS-h (9.9 mmol g−1 h−1) prepared by impregnation-hydrothermal sulfurization. The enhanced activity originates from the strongly coupled interface between exsolved NiS and CdS that efficiently promote the charge separation, while the exsolved NiS nanoparticles serve as highly active H2 evolution sites. Moreover, the strongly coupled interfaces enable improved H2 evolution stability for 2% NiS/CdS-e over a 30-h cycling reaction. This work provides an effective strategy toward strongly coupled cocatalyst/semiconductor photocatalysts for efficient solar energy conversion.