One-Step Hydrothermal Synthesis of an Orthorhombic WO₃·H2O/TiO₂ Heterojunction and its Photocatalytic Activity

Abstract

The main issues that limit the large-scale application of TiO2 in photocatalysis is its low utilization of solar energy and high recombination rate of photogenerated charges. To overcome these limitations, a type II WO3·H2O/TiO2 heterojunction has been prepared via a one-step mild hydrothermal method that uses Na2WO4·2H2O and P25 as the starting materials and proceeds at 150°C without requiring any post-heat treatment for crystallization, special solvents or additives. The XRD and HRTEM results show that the prepared powders were composed of orthorhombic WO3·H2O and TiO2, and demonstrate the existence of the WO3·H2O/TiO2 heterojunctions. The photocatalytic activity of the as-prepared WO3·H2O/TiO2 heterojunction powders was investigated by using the degradation of phenol. The WO3·H2O/TiO2 heterojunction powders exhibited the best photocatalytic performance when the nominal W/Ti ratio was 6.57%, and showed better photocatalytic performance than commercial P25 and orthorhombic WO3·H2O.