In situ growth of TiO₂ nanoparticles on nitrogen-doped Ti₃C₂ with isopropyl amine toward enhanced photocatalytic...

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.