Boosting solar driven hydrogen production rate of Cu2S@CdS p-n heterostructures and Cu Cd1-S nanorods

To improve CdS photocatalytic activity, both CuxCd1-xS nanorods and Cu2S@CdS p-n heterostructures have been prepared with a simple solvothermal method. The results showed that the maximum H2 generation rate is equal to 10 mmol h−1 g−1 and 12.1 mmol h−1 g−1 for samples 0.3-Cu2S@CdS and Cu0.1Cd0.9S, respectively, which are nearly 9 and 12 times larger than that of CdS (1.2 mmol h−1 g−1) without using Pt as the co-catalyst. The measurements of the light absorption revealed that the samples Cu2S@CdS p-n heterostructures and CuxCd1-xS nanorods have an increased visible light absorption. Band structure revealed that Cu2S@CdS p-n composite is a type-II heterostructure, which facilitates the separation of photoexcited charge carriers. Furthermore, as the Cu-doping CdS introduced a defect level, which induced the increase of carrier density, and the defect energy level in Cu0.1Cd0.9S and the band energy in CdS form a type-II heterostructure. Due to the appropriate band structure and stronger light absorption, Cu2S@CdS p-n heterostructures and Cu+-doping CdS demonstrated an improved photocatalytic activity and stability.