Remarkable enhancement of visible light driven photocatalytic performance of TiO2 by simultaneously doping with C, N, and S

Abstract

• Eg of TiO 2 was reduced from 3.34 eV to 1.90 eV by doping TiO 2 with C,N,S elements. • Doping TiO 2 with C,N,S significantly improved the photocatalytic activity of TiO 2 . • Optimal photocatalyst dose and initial concentration of RhB were respectively 1.8 g/L and 20 mg/L. • Photocatalytic degradation of RhB followed the first-order kinetics. • C,N,S tri-doped TiO 2 catalyst was highly stable and effective to degrade RhB in solutions. TiO 2 modified with C, N and S were produced by hydrothermal treatment and sol–gel method using thiourea as the precursor. The characteristic of the materials were examined by means of XPS, XRD, UV–VIS, SEM, EDX, and FT-IR. The results showed that C, N and S were successfully doped into TiO 2 lattice, leading to a decline in recombination rate of electrons/holes, and a shift of absorption edge of TiO 2 to visible light region. The photocatalytic performance of as synthesized catalysts were evaluated via the degradation of rhodamine B under visible light irradiation. N,C,S-TiO 2 demonstrated the highest photocatalytic efficiency and a perspective recyclable potential. The optimal photocatalyst dose was 1.8 g/L, and the best RhB initial concentration was 20 mg/L. At the optimal conditions, almost 100% of RhB were removed after 1.5 h. The photodegradation of RhB followed the seudo first-order kinetics, with the maximum rate constant of 0.0410 min −1 .