Spatial Charge Separation and Transfer in L-Cysteine Capped NiCoP/CdS Nano-Heterojunction Activated with Intimate Covalent Bonding for High-Quantum-Yield Photocatalytic Hydrogen Evolution

摘要

Constructing a highly efficient, stable and cost-effective heterojunction nanostructure catalyst for the solar-tofuel conversion is critical but challenging. Herein, I reported the synthesis of c-cysteine (L-Cys) capped Ni2-xCoxP (0 <= x <= 2)/CdS heterostructures that enable efficient spatial charge separation and transfer for solar hydrogen generation. A unique covalent bond formed via L-Cys between NiCoP and CdS that produces vast number of heterojunctions and abundant catalytic active sites for H-2 production. FTIR and XPS results indicate that L-Cys capped NiCoP was tightly deposited on the surface of CdS through a covalent bond between thiol and Cd. The 40 wt% L-Cys capped NiCoP/CdS is found to have the best photocatalytic performance and led to excellent stability for 192 h. As a result, the L-Cys capped NiCoP/CdS composite exhibited a H-2 evolution rate of 218 mmol g(-1) h(-1) and achieved a very high apparent quantum yield of 76.3% at 420 nm.