N-Cdots-decorated TiO2(B)/anatase microspheres with high photocatalytic performance in visible light

Abstract Nitrogen-doped carbon dots (N-Cdots) with enhanced absorption in visible light region were combined with TiO2(B)/anatase (TiO2(A + B)) microspheres consist of nanosheets via a one-step synthesis. The successful connection of N-Cdots and TiO2 substrate was confirmed by the appearance of new Ti–O–C bond. The degradation rate of Rhodamine B (RhB) for N-Cdots@TiO2(B)/anatase was improved to seven times higher than that of initial TiO2(B) microspheres under full spectrum illumination. N-Cdots@TiO2(B)/anatase photocatalyst also exhibited high photocatalytic ability under visible light irradiation. The possible mechanism was proposed in two irradiation conditions. N-Cdots act as a semiconductor to generate electrons and holes. The electrons were transferred to the conduction band of TiO2(B) and anatase, which improved the visible light utilization efficiency. Meanwhile, the heterophase structure of TiO2(A + B) substrate restrained the recombination of electron-hole pairs. It is the synergistic effect of heterophase and N-Cdots that enhanced the photocatalytic performance.