NiSe2 as Co-Catalyst with CdS: Nanocomposites for High-Performance Photodriven Hydrogen Evolution under Visible-Light Irradiation

One-dimensional NiSe2/CdS nanocomposites (NCs), with NiSe2 nanoparticles (NPs) integrated onto the surface of CdS nanowires (NWs) were designed and fabricated through a two-step in situ solvothermal method. Density functional theory (DFT) calculations showed that NiSe2 plays an important role in enhancing photocatalystic hydrogen (H-2) production when coupled with CdS catalyst, which arises from 1) the contribution of Ni 3d and Se 4p orbitals to the electronic structures and 2) the charge redistribution at the interface region of the heterostructure results in efficient promotion of the charge transfer and separation of the photogenerated electron-hole pairs. Under visible-light illumination (lambda >= 400 nm), the NCs showed improved photocatalytic H-2-generation activity in the presence of lactic acid. The peak value of 7610.1 mu mol h(-1) g(-1) for H-2 production was achieved with an apparent quantum efficiency (AQE) of 41.68 % when the Ni/Cd ratio was set to 10 %, which was approximately 48 times higher than that of bare CdS NWs. Photoelectrochemical measurements also confirmed the pivotal role of NiSe2 in the improvement of the H-2-evolution performance of NiSe2/CdS NCs, which is consistent with the DFT investigations.