In situ phase evolution of TiO2/Ti3C2Tx heterojunction for enhancing adsorption and photocatalytic degradation

Constructing an exposed facet TiO2/Ti3C2Tx heterojunction with chemical bonding (Ti-O-Ti), and its narrower band structure (2.1 eV) can enhance the separation of photoinduced electron-hole pairs. In this work, an in situ solvothermal method for controlling the oxidation of Ti3C2Tx is utilized with F- (0, 0.5, 1.5, 2.5 mmol NaBF4) as the cosurfactant, wherein the concentration of F- can adjust the percentages of (101) and (001) TiO2 which are embedded in the layers of Ti3C2Tx. When the cosurfactant is 1.5 mmol F-, (101) and (001) TiO2/Ti3C2Tx (TT-15) heterojunction to adsorb and photo-catalytically degrade organic dyes. The specific surface area of TT-15 heterojunction is 108.37 m(2).g(-1), which is effective in increasing the interfacial area between the organic dyes and the photocatalyst. The photocatalytic degradation efficiencies of methylene blue (MB) and methyl orange (MO) of TT-15 exceed 97.5% and 79.5% under 500 W mercury light in 30 min, and the kinetic constants of MB and MO degradation reached 0.10711 min(-1) and 0.04537 min(-1), respectively. Furthermore, there is a synergistic effect between the exposed facet TiO2/Ti3C2Tx heterojunction and the photocatalytic reaction, as demonstrated by the transfer of photogenerated carriers and the generation of center dot O-2(-) and center dot OH, which can improve the performance of the catalytic degradation of organic dyes.