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

Abstract

Constructing a highly efficient, stable and cost-effective heterojunction nanostructure catalyst for the solar-to-fuel conversion is critical but challenging. Herein, I reported the synthesis of l-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 H2 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 H2 evolution rate of 218 mmol g−1 h−1 and achieved a very high apparent quantum yield of 76.3% at 420 nm.