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 effi-ciently 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/semi-conductor photocatalysts for efficient solar energy conversion.