Covalent-bond-enhanced photocatalytic hydrogen evolution of C_3N_4/CoP_x with L-cysteine molecule as bridging ligands

摘要

Serious interface carrier recombination leads to moderated photocatalytic performance of carbon nitride (C3N4), and the realization of their strongly covalent bonding with co-catalysts can efficiently inhibit this. In this article, C3N4 nanosheets are first functionalized with L-cysteine molecules to form C-SH bonds, and then the photo-deposited CoPx NPs are covalently bonded with C3N4 with L-cysteine molecules as bridging ligands, which can efficiently reduce the C3N4/CoPx interface impedance. Their optimal hydrogen evolution rate and apparent quantum efficiency at 420 nm are 4.12 mmolg(-1)h(-1) and 3.74%, respectively, which are 17.2 and 13.9 times that C3N4/CoPx reference without L-cysteine bridging ligands, mainly due to the reduced C3N4/CoPx interface impedance. This work proposes a general solution to inhibit interface carrier recombination in nanocomposites by introduction of bridging ligands.