Photocatalytic H2O2 production using Ti3C2 MXene as a non-noble metal cocatalyst

[Display omitted] •A 2D MXene Ti3C2 was used as a cocatalyst in photocatalytic H2O2 production.•The photocatalytic H2O2 production of 10 %-Ti3C2/TiO2 is 21 times higher than P25.•Ti3C2 can prevent surface TiOOH generation to inhibit H2O2 photodecomposition.•H2O2 production follows a two-step sequential single-electron reduction mechanism. Photocatalytic H2O2 production by O2 reduction is an environmental-friendly process for solar light conversion to chemical energy. In this work, Ti3C2 MXene was used as a non-noble metal cocatalyst to load on P25 as Ti3C2/TiO2 (TC/TO) photocatalysts for photocatalytic H2O2 synthesis. A H2O2 formation rate (179.7 μmol L−1 h−1) of the optimized 10 %-TC/TO composite was obtained to be over 21 folds as high as that of P25 under UV light. Radical quenching experiments and superoxide radical detection confirmed the superoxide radical as the primary intermediate, suggesting the O2 reduction in two-step single-electron indirect reaction. The higher activity of TC/TO can be attributed to the functions of Ti3C2 MXene in accelerating the separation and transfer of photogenerated electron-hole pairs, suppressing their recombination, and blocking the surface TiOOH formation. This work proves the promising roles of Ti3C2 MXene in the photocatalytic reaction and further expands their new applications in photocatalysis.