| Photocatalytic technology has a broad application in the field of environmental pollution,due to the advantages of high efficiency,energy saving,environmental friendliness,and thorough degradation of pollutants.The intrinsic problems such as narrow light response range,fast recombination of excited electrons and holes,extensively exist in photocatalysts,typically TiO2.Therefore,developing photocatalysts with visible light response has become the research hotspot.Bi2MoO6 was adopted in this article to investigate the effects of synthetic methods,solvent and surfactant types on the photocatalytic activity,and the synthesized catalysts were further doped with rare-earth(RE)elements.Novel strategy of building Z-schemed Bi2MoO6/Ag/TiO2 photocatalyst was implemented by depositing noble metal on Bi2MoO6 and subsequently combining with TiO2 to further improve its photocatalytic activity.The main research contents and the obtained results are as follows:Bi2MoO6 samples with different morphologies have been prepared using co-precipitation and hydro-thermal methods.Octahedral-,spherical-,and plate-like particles have been obtained by changing some external factors including preparation methods,solvent types,and surfactants.Our results suggested that pure Bi2MoO6 phase with nanoplate morphology are easily obtained via hydrothermal preparation method using ethylene glycol solvent.The photocatalytic and photoelectric properties of these Bi2MoO6 samples have also been investigated in detail.Moreover,the photocatalytic activity was enhanced with addition of surfactants,such as Polyvinylpyrrolidone(PVP),Sodium dodecyl sulfate(SDS),and cety-trimethylammonium bromide(CTAB).The excellent photocatalytic activity for Bi2MoO6 phase with CTAB addition was nearly 100%.It may be ascribed to the specifically exposed facets structure,which is related to larger visible light absorption and improved separation of photogenerated charge carriers.Bi2MoO6 catalysts with rare earth dopants have been successfully synthesized using the facile hydrothermal method.The morphologies,phase content,and optical absorption properties of these catalysts with rare earth dopants are measured via X-ray diffractometer(XRD),X-ray photoelectron spectrometer(XPS),Scanning electron microscope(SEM),and UV-vis diffuse reflectance spectra(UV-DRS)techniques.Our results suggested that in the Nd and Sm-doping cases,one new phase Bi3.64Mo0.36O6.55 appeared.The morphologies and microstructures of Bi2MoO6 system have also been changed correspondingly.The photocatalytic activities of these doped Bi2MoO6 samples were also evaluated via the photodegradation of RhB under visible light irradiation.The results indicated that,with rare earth doping,the photocatalytic activities of these Bi2MoO6 samples have been greatly improved.Moreover,the mechanism about the enhancement of photocatalytic activity has also been discussed.Visible-light-driven photocatalyst Ag/Bi2MoO6 was successfully synthesized via a facile hydrothermal route.Ag was uniformly dispersed on the surface of Bi2MoO6 nanosheets.The photocatalytic performance of Ag/Bi2MoO6 composites was evaluated by the degradation of Rhodamine B(RhB).The Ag/Bi2MoO6 nanocomposite exhibited a higher photocatalytic activity as compared to pure Bi2MoO6.Moreover,the 7 wt%Ag-loaded Bi2MoO6 showed the optimal photocatalytic performance in the degradation of RhB.The photogenerated holes(h+)and superoxide radical anions(·O2-)were found to be the primary reactive species in the degradation of RhB dye in aqueous solution.The Bi2MoO6/TiO2 and Bi2MoO6/Ag/TiO2 composites were solvothermally synthesized via a simple mixing method.They are characterized by X-ray diffraction.(XRD),X-ray photoelectron spectroscopy(XPS),(high resolution)transmission electron microscopy((HR)TEM).The Bi2MoO6/TiO2 and Bi2MoO6/Ag/TiO2 composites exhibited higher photocatalytic activity than pure Bi2MoO6.100%of the RhB dye molecules could be decomposed over Bi2MoO6/Ag/TiO2 composite in 120 min.The enhanced photocatalytic activity of Bi2MoO6/TiO2 and Bi2MoO6/Ag/TiO2 composite was attributed to the efficient separation of photoinduced electrons and holes.A detail mechanism for the enhanced photocatalytic activity is discussed. |
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