Efficient Visible Light Active CaFe₂O₄/WO₃ Based Composite Photocatalysts: Effect of Interfacial Modification

Abstract

We report on the photocatalytic decomposition of acetaldehyde over CaFe 2 O 4 (CFO)/WO 3 based composite photocatalysts under visible light irradiation, emphasizing the photocatalyst composition optimization and the effect of interface modification on photocatalytic activity. Although heat treatment caused deactivation of CFO/WO 3 composite photocatalyst, the photocatalytic activity of WO 3 was improved by simply mixing with CFO, and 5 wt % CFO coupled WO 3 showed the optimized performance. Ag and ITO coating on the CFO particle surface obviously promoted the photocatalytic activity of the CFO/WO 3 composite. The CFO/Ag (or ITO)/WO 3 composite photocatalyst could completely decompose acetaldehyde under visible light irradiation. X-ray photoelectron spectra suggested that the photoinduced self-reduction in WO 3 was effectively suppressed after coupling with CFO. The possible mechanism of the surface modification effects was discussed.