CoSe2 modified Se-decorated CdS nanowire Schottky heterojunctions for highly efficient photocatalytic hydrogen evolution

Novel CoSe nanobelts/Se-decorated CdS nanowires heterojunctions were successfully constructed via combining strategies of Se-doping and in situ loading of CoSe nanobelts. Under visible-light (λ ≥ 400 nm) irradiation, the CoSe/CdSSe nanocomposites exhibit significantly enhanced photocatalytic H-evolution activities. The peak value of the H-generation rate of 13894.8 μmol·h·g is achieved with an apparent quantum efficiency (AQE) of 76.1%, which is approximate 66.7 times higher than that of pure CdS nanowires. Experimental investigations and theoretical calculations demonstrate that the enhanced photocatalytic H-evolution performance originates from the synergetic effects of 1) the Se-doping to form CdSSe nanowires, which can reduce the electrostatic potential energy of CdS catalyst to promote electrons migration for reducing the recombination efficiency of electron/hole pairs; and 2) the in situ loading of CoSe co-catalyst to construct the Schottky heterojunction between CoSe and CdSSe nanowires, which can not only efficiently boost the separation of charge carriers, but also provide sufficient active sites for reducing H to H subsequently.