Enhanced photocatalytic activity of (Mo, C)-codoped anatase TiO₂ nanoparticles for degradation of methyl orange under simulated solar irradiation

C-doped, Mo-doped, and (Mo, C)-codoped TiO₂ photocatalysts were prepared by a sol-gel process. The photocatalytic activity was evaluated by the photocatalytic degradation of methyl orange (MO) under simulated solar irradiation. Results indicated that both monodoped and codoped TiO₂ exhibited better visible light absorption behavior and narrower energy gap than pure TiO₂, and codoped TiO₂ showed a slightly higher adsorption property in the dark because of higher Brunauer–Emmett–Teller-specific surface area. The photocatalytic activity of monodoped TiO₂ was also enhanced, and the (0.04% Mo, C)-codoped sample had the best photocatalytic activity for degrading MO among all of the samples. The reason can be ascribed to the synergistic effect due to Mo and C doping. Furthermore, the transfer pathways of photoinduced carriers and photocatalytic reaction mechanism of (Mo, C)-codoped TiO₂ was first investigated.