The enhancement of photocatalytic CO2 reduction by the in situ growth of TiO2 on Ti3C2 MXene

The photocatalytic reduction of CO2 to solar fuel can solve energy crisis and global warming problems. Herein, TiO2/Ti3C2 was prepared via an improved sol-gel method and applied for the photocatalytic reduction of CO2. TEM, Raman, XPS, and other characterization results proved that TiO2 was grown in situ on Ti3C2 and formed a Schottky junction in the TiO2/Ti3C2 composite. The production rates of CO and CH4 for the optimal TiO2/Ti3C2 were 2.8 and 4.0 times higher than that of TiO2, respectively. The enhanced photocatalytic performance was due to the intimate interface between TiO2 and Ti3C2 with the formation of a Schottky junction, which promoted the separation of electron-hole pairs. The effect of the adsorption of TEOA on the photocatalytic performance was studied. Also, the mechanism for the photocatalytic reduction of CO2 in the TiO2/Ti3C2 system was proposed. This study shows that the intimate interface formed via the in situ growth of TiO2 on Ti3C2 is beneficial for the photocatalytic reduction of CO2.