Visible-Light-Induced Hydrogenation of C=C Bonds by Hydrazine over Ultrathin Layered Double Hydroxide Nanosheets

The reduction of C=C is of great importance, while H-2 is the most widely used source usually in the harsh condition in the industry. However, under mild conditions, the H-2-free reduction of C=C bonds to more valuable products is one of the challenges to be solved in recent years. Herein, ZnCr-layered double hydroxide nanosheets (ZnCr-LDH-NS) were synthesized by the coprecipitation method and showed efficient reduction activity in carbon-carbon multiple bonds using hydrazine as a reducing agent under visible-light irradiation (400-800 nm) with a 74.12% conversion of ciscyclooctene. The X-ray absorption fine structure (XAFS) and electron spin resonance (ESR) revealed that oxygen defects and metal defects were formed on the surface of ZnCr-LDH-NS, providing a more suitable band structure to promote the reduction of olefins by hydrazine. This work may serve as a guide in designing efficient photocatalysts for hydrogenation using hydrazine as a reduction agent.