Light absorption and photocatalytic activity enhanced by in situ formation of uniform TiO2 nanoparticles on two-dimensional Ti3C2Tx surface

Abstract Ti3C2Tx surface was functionalized with uniform TiO2 nanoparticles (NPs) to form layered TiO2/Ti3C2Tx heterojunctions by an in situ solvothermal oxidation method. The resulting TiO2 NPs were connected to Ti3C2Tx species via O–Ti–O bonds. The TiO2/Ti3C2Tx (TT-190) heterojunctions exhibited the optimal bandgap of 2.11 eV at a reaction temperature of 190 °C, which was favorable for the absorption of visible light. The photocatalytic activity of TT-190 was examined by studying the photodegradation of mono-azo dye methylene red (MR) and di-azo dye congo red (CR). The MR degradation rate over TT-190 exceeded 96.1% after 120 min of irradiation with a 300 W xenon lamp, while the CR degradation rate over TT-190 under the same conditions was only 87.5%. The enhanced photocatalytic performance for azo dye degradation with TT-190 derive from the charge transfer and the generation of active radical species ·O2–. This work provides an alternative method for the fabrication of controllable uniform TiO2 NPs on the two-dimensional Ti3C2Tx surface, thus improving its photocatalytic activity.