Titania nanotubes modified with sulfuric acid (S-TNTs) were synthesized through hydrothermal treatment and impregnation method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence spectra (PL). Fourier transform infrared spectroscopy (FT-IR), BET surface area and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of S-TNTs were investigated by the glyphosate degradation. The lower the PL intensity, the higher the photocatalytic activity. The sulfuric acid modification enhanced the photocatalytic activity of TNTs, and 7%S-TNTs calcined at 400 degrees C showed the highest photocatalytic activity. The photocatalytic performance of as-prepared S-TNTs was strongly related with the sulfuric acid concentration and the degree of crystallinity. The nanotube morphology, the specific surface area, as well as the crystallite size also had important impact on the photocatalytic activity of S-TNTs. (C) 2012 Elsevier B.V. All rights reserved.