RESUMO
The photocatalytic properties of silver nanoparticles (Ag NPs) coupled with tungsten oxide (WO3) nanocrystals are investigated to understand structural effects of the WO3 nanocrystals in selective oxidation of cyclohexane (CyH). The photocatalytic activity of monolayer hydrated WO3 nanosheet - Ag nanoparticle composites (WO3 NSs-Ag NPs) is 1.3 times higher than that of WO3 nanocube - Ag nanoparticle composites (WO3 NCs-Ag NPs). The highest cyclohexane conversion of 40.2% with cyclohexanol and cylohexanone (KA oil) selectivity of 97.0% is achieved by the photocatalyst of WO3 NSs-Ag NPs under solar-light irradiation at room temperature. The WO3 NSs-Ag NPs shows good photocatalytic stability without evident decline of catalytic activity after ten cycles. The improved photocatalytic activity in the oxidation of cyclohexane by WO3 NSs-Ag NPs is mainly due to the facilitated generation of high-reactive hydroxyl radical (OH), which is caused by the enhanced light absorption by surface plasmon resonance (SPR) effect of Ag NPs, and the effective charge transfer on the surface of WO3 monolayer structure. The design and structural analysis of the WO3 NSs-Ag NPs in this research may provide a novel approach for the further development of high-performance photocatalyst.
