Construction of Porous Tubular InS@InO with Plasma Treatment-Derived Oxygen Vacancies for Efficient Photocatalytic HO Production in Pure Water Via Two-Electron Reduction.

Tubular InO was fabricated by the annealing of In-MIL-68 and further treated by Ar plasma to yield oxygen vacancies (O) followed by the growth of InS nanoflowers. Unexpectedly, the resulting porous InS@InO composites were discovered to display a broad visible-light response and especially enhanced capacities for efficient photocatalytic production of HO in pure water, with a rate of 4.59 μmol·g·min. 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 sites on the composites might tune the HO 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 active sites. Importantly, it may provide a promising defect-induced strategy of two-electron reduction triggered by the plasma treatment for the efficient photocatalytic HO production under visible light.