Self-doped Ti3+-enhanced TiO2 nanoparticles with a high-performance photocatalysis

► TiO2 self-doped with Ti3+ are successfully synthesized by a simple solvothermal method. ► Low-cost NaBH4 is used as a reductant. ► HCl solution is used to wash out the by-product and carbonaceous impurities coated on the catalysts surface. ► Visible-light photocatalytic activity of Ti3+-doped TiO2 depends on the amount of Ti3+ added. ► There is no significant impact of Ti3+ doping on its UV-light photocatalytic activity.