Construction of Porous Tubular In2S3@In2O3 with Plasma Treatment-Derived Oxygen Vacancies for Efficient Photocatalytic H2O2 Production in Pure Water Via Two-Electron Reduction

Tubular In2O3 was fabricated by the annealing of In-MIL-68 and further treated by Ar plasma to yield oxygen vacancies (Ov) followed by the growth of In2S3 nanoflowers. Unexpectedly, the resulting porous In2S3@In2O3 composites were discovered to display a broad visible-light response and especially enhanced capacities for efficient photocatalytic production of H2O2 in pure water, with a rate of 4.59 μmol·g–1·min–1. An apparent quantum yield of 28.9% at 420 nm can also be expected without the use of noble metals or organic scavengers. Herein, the high light utilization might be profited from their porous tubular heterostructure for powerful "light captivity". Moreover, the Ar plasma-derived Ov sites on the composites might tune the H2O2 generation route from the single-electron reduction to the two-electron one toward the significantly enhanced photocatalysis, as validated by the Koutecky–Levich plots. This work demonstrates a new perspective of designing porous heterostructures with the advantages of high light harvest and plasma-derived Ov active sites. Importantly, it may provide a promising defect-induced strategy of two-electron reduction triggered by the plasma treatment for the efficient photocatalytic H2O2 production under visible light.