Improvement of photocatalytic oxidation activity on a WO3/TiO2 heterojunction composite photocatalyst with broad spectral response

Abstract

WO3/TiO2 that can efficiently use ultraviolet and visible light simultaneously was designed and investigated for photocatalytic O-2 evolution. It was found that a remarkable synergistic effect on the photocatalytic activity is obtained between WO3 and TiO2 under UV-visible light illumination. The optimum photocatalyst WO3/TiO2 shows an evolution rate of 281 mu mol h(-1) g(-1) of oxygen, which is even higher than the summation of the photocatalytic activities of WO3 and TiO2. The UV-visible spectra indicate that WO3/TiO2 have a broad spectral response. XRD and Raman spectra demonstrated the formation of the bulk and surface phases of WO3. The HRTEM image shows a close contact at the interface of WO3 and TiO2, indicating the formation of heterojunctions. Thus, it is proposed that the broad light absorption and efficient electron transfer via heterojunctions of WO3/TiO2 account for the higher photocatalytic activity of WO3/TiO2.