Co3O4/CdS p-n heterojunction for enhancing photocatalytic hydrogen production: Co-S bond as a bridge for electron transfer

Photocatalytic hydrogen production from water splitting production is a promising strategy to solve the energy crisis and environmental pollution. In the present work, Co3O4/CdS composites were prepared by ultrasonication and stirring, and used for photocatalytic water splitting. The results showed a Co-S chemical bonds were formed at the interfaces between the Co3O4 and the CdS, which promoted the charge transfer rate between the CdS and Co3O4. Meanwhile, the recombination of the electron-hole pairs was further restrained by the Co3O4/CdS p-n heterojunction. The 10%-Co3O4/CdS composites exhibited an excellent photocatalytic hydrogen production rate of 142.62 μmol∙h−1, which was 20 times higher than that of CdS (6.85 μmol∙h−1), and the Co3O4/CdS showed excellent stability in the photocatalytic water splitting reaction. Moreover, a formation process of Co3O4/CdS p-n heterojunction and a mechanism of Co3O4/CdS p-n heterojunction avoiding the recombination of photocatalytic electrons and holes to enhance photocatalytic activity was proposed.