Boosting H2O2 production via two-electron oxygen reduction with O-doped g-C3N4 decorated with Ti3C2Tx quantum dots

Photocatalytic synthesis of H2O2 with g-C3N4 holds great promise for converting solar energy into chemical energy, but it remains constrained by the narrow optical absorption range and rapid charge recombination. To overcome these challenges, Ti3C2Tx MXene quantum dots (TQDs), known for their ease of carrier regulation and strong visible light absorption, were incorporated into O-doped g-C3N4 (O-CN) to form TQDs-modified O-CN (OCN@TQDs) with a Schottky heterojunction. Attributed to such structural design, the H2O2 production was promoted through the two-step two-electron oxygen reduction pathway, with center dot O2- serving as the primary intermediate. The photocatalytic H2O2 production rate over optimized O-CN@TQDs reached 868.9 mu mol g- 1 h- 1 under visible light irradiation, which was 10.8 times higher than that of the pristine g-C3N4. This study underscores the potential of judiciously selecting suitable semiconductor and metal-like materials to construct Schottky heterojunctions for the efficient photocatalytic production of H2O2.