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 In 2 O 3 was fabricated by the annealing of In-MIL-68 and further treated by Ar plasma to yield oxygen vacancies (O v ) followed by the growth of In 2 S 3 nanoflowers. Unexpectedly, the resulting porous In 2 S 3 @In 2 O 3 composites were discovered to display a broad visible-light response and especially enhanced capacities for efficient photocatalytic production of H 2 O 2 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 O v sites on the composites might tune the H 2 O 2 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 O v active sites. Importantly, it may provide a promising defect-induced strategy of two-electron reduction triggered by the plasma treatment for the efficient photocatalytic H 2 O 2 production under visible light.