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 O₂ 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 μmol 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.