LAUSR

Construction of heterojunction and nitrogen doping is an effective approach for synthesizing photocatalysts with high quantum yield and efficient electron-hole separation. 2D MXene Ti3C2 has been considered a good carbonaceous nanomaterial for designing heterojunction, while the original surface groups and stacked structure limit the electron-hole separation. Herein, a hybrid of nitrogen-doped Ti3C2 nanosheets and TiO2 nanoparticles (NPs) composed of TiO2 NPs in situ growing on isopropyl amine (iPA) modified Ti3C2 (iN-Ti3C2) was developed for the first time. The novel iN-Ti3C2/TiO2 hybrid exhibited an excellent ultraviolet-light photodegradation of methylene blue (MB), with a degradation rate (0.02642 min-1) significantly higher than that of pure TiO2 NPs, bulk-Ti3C2/TiO2, dimethyl sulfoxide modified Ti3C2/TiO2 hybrid, and hydrazine monohydrate modified Ti3C2/TiO2 hybrid. The formation of heterojunction between iN-Ti3C2 and TiO2 and its role in the photocatalysis were systematically analyzed using various characterization techniques and density functional theory calculation. The iPA modification exfoliated Ti3C2 and doped N on Ti3C2 nanosheets; the in situ grown TiO2 NPs formed efficient heterojunctions with the nanosheets; the N-doping facilitated electron migration in Ti3C2 and inhibited the recombination of photogenerated electron-hole pairs; •OH dominated the photodegradation of MB. This work provides a new approach of constructing efficient photocatalysts for the treatment of organics-polluted water.