The Comparison of Property and Visible Light Activity between Bulk and Surface Doped N-TiO2 Prepared by Sol-gel and N2-plasma Treatment

A modified sol-gel method and N-2-plasma treatment were used to prepare bulk and surface doped N-TiO2, respectively. XRD, TEM, UV-vis spectroscopy, N-2 adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared TiO2 samples. The N doping did not change the phase composition and particle sizes of TiO2 samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N-TiO2 prepared by N-2-plasma was much higher than that of bulk doped N-TiO2 prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.