Increased Active Sites by in Situ Growth of CoP Quantum Dots on CdS/rGO To Achieve Efficient Photocatalytic H₂ Production

Constructing numerous surface active sites to realize quick charge transfer and efficient adsorption of water molecule is of significant importance for extremely improving the photocatalytic H2 production activity of catalyst. In this work, new ternary CoP/CdS/rGO photocatalysts were prepared using hydrothermal assisted by thermal phosphorization method. In situ growth of CoP quantum dots (QDs) is employed as the surface active sites on the CdS/rGO surface to accelerate photogenerated electrons transport and strengthen surface photoreaction of the samples. According to the experimental and DFT calculation results, an internal electric field is built at the interface of CdS/graphene and CoP/graphene, respectively. Under solar light irradiation, the photogenerated electrons would directionally transfer from CdS to CoP QDs via the “charge transfer channel” of graphene, resulting in the efficient separation of electron–hole pairs. As a result, the ternary composites achieve unexpectedly high-efficient photocatalytic hydrogen generation activities (1.104 mmol·h–1), which exceed 6.8 times that of CdS. This research verifies that the introduction of more active sites is the key factor for the improvement of photocatalytic H2 generation and provides a valuable strategy for the synthesis of high performance graphene-based photocatalyst.