A study on the synergistic adsorptive and photocatalytic activities of TiO2−xNx/Beta composite catalysts under visible light irradiation

A series of TiO2−xNx/Beta composite samples were prepared by coating the nitrogen-doped titania on the Beta zeolite using a simple sol–gel method. Samples were characterized by nitrogen adsorption–desorption, XRD, TEM, UV–vis, XPS and FTIR techniques. The photocatalytic activities were evaluated by the degradation of methylene blue under visible light irradiation. The synergistic effect between absorption and photocatalysis of the TiO2−xNx/Beta composite materials was found in terms of methylene blue removal efficiency under visible light irradiation, since the assisting adsorption ability from H-Beta zeolite could supply a concentrated pollutant environment around titania active sites. The highest photocatalytic efficiency was obtained on the 10% TiO2−xNx-coated composite sample, which was probably due to the better dispersion of titania on the support. Furthermore, the TiO2−xNx/Beta-10% catalyst was consistent to be the most efficient composite material tested for the photocatalytic degradation of methylene blue even in different pH environment.