Simultaneous H2 fuel evolution and value-added organic transformation from a one-dimensional noble-metal-free photocatalyst with spatially separated catalytic sites

Abstract

Replacing the sluggish O2-producing half-reaction with value-added organic oxidations in water photolysis systems is deemed more practical to generate H2 fuels. While loading of dual cocatalysts for both half-reactions onto nanoscale photocatalysts is highly beneficial for photocatalysis, developing such nanomaterials that are low-cost, stable and easy-to-synthesize remains challenging. Here, noble-metal-free CdS-Co3O4-NiSx nanodumbbells with spatially separated half-reaction sites are designed to simultaneously generate H2 and oxidize benzylamine without any sacrificial agent. In this nanoarchitecture, electron-collecting NiSx and hole-collecting Co3O4 are anchored at the tips and sidewall of CdS nanowires, respectively, to lower the proton reduction and benzylamine oxidation energy barriers, respectively, thus establishing a dual-functional photocatalytic redox system. With significantly promoted charge separation and half-reaction kinetics, the nanodumbbells can produce H2 (47 mmol∙g−1∙h−1) ca. 70 times faster than pure CdS, along with simultaneous benzylamine oxidation. Our findings provide a viable one-dimensional photocatalyst design strategy for various coupled half-reactions.