A novel p-n heterojunction Mn0.25Cd0.75S/Co3O4 for highly efficient photocatalytic H2 evolution under visible light irradiation

The construction of p-n heterojunction is an efficient strategy to restrain photogenerated charge carriers recombination and enhance the photocatalytic efficiency toward H-2 evolution from water splitting. Herein a novel p-n heterojunction Mn0.25Cd0.75S/Co3O4 was synthesized via facile hydrothermal method. Photocatalytic H-2 evolution of as-synthesized Mn0.25Cd0.75S/Co3O4 composites in the absence of noble metal co-catalysts under visible light irradiation (lambda >= 400 nm) was investigated. The results demonstrated that photocatalytic H-2 evolution of Mn0.25Cd0.75S was significantly enhanced by loading Co3O4 nanoparticles. It was confirmed that 0.48 wt% of Co3O4 loading content achieved the highest H-2 evolution rate of 25.71 mmol/g/h, which was about 5.35 times higher than that of pure Mn0.25Cd0.75S. The remarkably improved photocatalytic activity could be attributed to the formation of the p-n junction at the interface between Mn0.25Cd0.75S and Co3O4, effectively promoting interfacial charge transfer and separation. This work revealed that the p-n heterojunction Mn0.25Cd0.75S/Co3O4 may be a promising candidate for efficient energy conversion. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.