Sacrificial-agent-free artificial photosynthesis of hydrogen peroxide over step-scheme WO₃/NiS hybrid nanofibers

Developing low-cost and durable photocatalysts for sacrificial-agent-free artificial photosynthesis of hydrogen peroxide is challenging. In this work, an all-inorganic hybrid nanofiber step-scheme photocatalyst, WO3/NiS (WONS), was constructed for efficient generation of hydrogen peroxide in pure water at ambient condition. The optimal photocatalyst, WONS35 % (with 35 wt% of NiS), exhibits remarkable efficiency in producing H2O2 at a rate of 2.59 mmol g(catalyst)(-1) h(-1) under visible light illumination, surpassing the H2O2 production rate of pristine WO3 and NiS by 11.3 and 16.7 times, respectively. WONS35 % demonstrates an apparent quantum yield of 4.97 % at a wavelength of 420 nm. The significantly enhanced photocatalytic performance can be ascribed to the synergistic effect of the improved charge separation and transfer induced by the step-scheme pathway and the highly selective two-electron oxygen reduction reaction (ORR) over the hybrid nanofiber photocatalyst.