Graphdiyne (g-CnH2n-2) boosting electron transfer over rational design and construction of CuI/Ni-MOF photocatalyst for efficient hydrogen evolution

Abstract

A CuI-graphdiyne/Ni-MOF ternary system was successfully constructed. Intially, CuI-graphdiyne was obtained by growth of GDY on the surface of CuI. Subequently, the CuI-graphdiyne was immobilized onto the surface of Ni-MOF using a simple physical stirring method. This, immobilization approach effectively reducing the accumulation of CuI-graphdiyne and increased the number of active sites for hydrogen evolution. Furthermore, a combination of various characterization techniques and energy band structures analysis was employed to propose the photocatalytic reaction mechanism between CuI and Ni-MOF. The proposed mechanism involves a Z-scheme heterojunction and suggests that the combination of CuI and Ni-MOF enhances the overall redox ability of the composite catalyst. By comparing CuI/Ni-MOF with CuI-graphdiyne/Ni-MOF, it was observed that the presence of graphdiyne as an electron-rich layer on CuI enhances the photocatalytic performance of CuI. Additionally, it facilitates electron transport between CuI and Ni-MOF, thereby improving the efficiency of photogenerated electron-hole complex separation. This experimental study provides valuable insight into the utilization of graphdiyne for enhancing transport in heterojunction.