Ti3+ self-doped TiO2 are successfully prepared via a simple one-step calcination method, by using low-cost NaBH4 as the reductant. The as-prepared samples are characterized by different techniques such as X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and Fourier transformation infrared spectroscopy (FTIR). EPR spectra confirm the presence of Ti3+ in the bulk of the samples rather than on the surface, which is the reason for the high photocatalytic performance of the catalyst under visible light irradiation. It is worth noting that the visible light absorption is enhanced after HCl washing, and the photocatalytic activity of Ti3+ self-doped TiO2 is proportional to the concentration of the doped Ti3+. Interestingly, the photocatalytic activity of the catalyst under UV light also increases after HCl washing treatment, which is caused by the increase of BET surface area. (C) 2014 Elsevier B.V. All rights reserved.