Improved oxidative degradation performance for doxycycline by In2O3/g-C3N4 composite photocatalyst coupling with persulfate and its efficient H2O2 production capacity

Photocatalysis utilizing clean light energy is a green solar energy conversion technology with the ability for pollutant degradation and energy production, which is one of the technologies to alleviate the crisis of environmental pollution and energy shortage. In this work, the cubic In2O3 modified g-C3N4 composite was prepared and coupled with persulfate (PS) for the catalytic oxidation of the antibiotic doxycycline (DOX). And the optimal degradation efficiency of DOX reached 99.3% under simulated sunlight irradiation. In addition, the H2O2 generation performance was investigated by oxygen reduction reaction (ORR). Almost all DOX (99.3%) was degraded within 60 min over the optimal system of In2O3/g-C3N4–5 + PS. And the optimal composite also demonstrated an excellent H2O2 yield of 336.3 μmol L−1 h−1 following the two-electron ORR. The higher separation and utilization of photogenerated electrons is the key reason for the improved catalytic activity of the composite.