Enhanced photocatalytic degradation performance of In₂O₃/g-C₃N₄ composites by coupling with H₂O₂

Environmental pollution by organic pollutants poses a great threat to the ecosystem and human development. Solar-powered catalytic oxidation technology can solve the existing energy and pollution crisis. Hence, in this work, cubic nano-In₂O₃ modified g-C₃N₄ composite was synthesized by in situ calcination, then it was coupled with hydrogen peroxide for the degradation of antibiotic under visible light. The results of SEM and XPS showed that In₂O₃ and g-C₃N₄ were closely combined. The catalytic oxidation efficiency of the antibiotic doxycycline was greatly improved when the as-prepared compound was coupled with hydrogen peroxide, and 88.2% of doxycycline was degraded within 80 min. By designing the active species inhibition test, it was found that a large number of hydroxyl radicals were generated in the system after adding hydrogen peroxide, which accelerated the degradation of the target. Hydrogen peroxide not only acts as a source of hydroxyl radical, but also as an active electron acceptor, which promotes the separation of photogenerated electron-hole pairs in the composite photocatalyst. Therefore, the double oxidation system formed by In₂O₃/g-C₃N₄ coupled with hydrogen peroxide can degrade the target at a higher rate. This work provided a research basis for the synthesis of In₂O₃ with regular morphology and simplified synthesis of In₂O₃/g-C₃N₄, and explored the practicability of the coupling method of double advanced oxidation for pollutant degradation.