Epitaxial growth of metastable phase α-Ag2MoO4 on WO3 surface: Visible light-driven photocatalysis, sterilization, and reaction mechanism

The metastable alpha-Ag(2)oO(4) was usually prepared under high pressure conditions, but it was successfully prepared by epitaxial growth on WO3 nanosheets at room temperature under normal pressure in this work. The interfacial structure of alpha-Ag(2)oO(4)/WO3 (AW) was characterized by XRD, SEM, TEM, and Raman spectra to explain the process of phase transformation from the beta phase to the alpha phase. The photocatalytic activities were evaluated by the degradation of methylene blue and Escherichia coli. The results indicate that AW-60 exhibits the best photocatalytic activity. The enhancement in photocatalytic performance is mainly due to the photogenerated electron flow between the components from WO3 to Ag2MoO4 in AW-60. The initial inactivation of E. coli is due to the decomposition of macromolecules with a typical mass range m/z of 2-7 kDa. The corresponding photocatalytic mechanism was proposed and confirmed by the measurements, such as BET, fluorescence spectrum, free radical trapping and the zeta potential of WO3 and AW-60. (C) 2019 Elsevier B.V. All rights reserved.