Syntheses And Characterization Of Photocatalytic Properties Bismuth Vanadate Nanomaterials

With industrialization and population growth, the environmental contaminationcaused by organic pollutants is becoming an overwhelming problem all over theworld.Therefore,The quest for renewable energy sources and the constant access toclean water resources are vital research challenges for modern society.Harvestingenergy directly from sunlight offers a desirable approach to solving the energychallenge with minimal environmental impact.Since Fujishima and Honda first reported the photocatalytic splitting of water onTiO2electrodes in1972, Photocatalyst TiO2has been extensively investigatedbecause of its non-toxicity, high chemical stability, photostability and inexpensive; H-owever, a large intrinsic band gap of TiO2,3.2eV for anatase, allows only a smallportion of the solar spectrum in the ultraviolet light region to be absorbed. Therefore,it is highly desirable to develop a photocatalyst that can use visible light in highefficiency under sunlight irradiation. So that Visible-light-driven photocatalystsBiVO4have attracted much attention recently.In this paper, we gave the definitions and properties of nanomaterials, andreviewed the current state and photocatalytic mechanism of some nanoscalephotocatalysts; In this chapter, we highlighted the structures, properties, synthesesand analytic methods of BiVO4nanomaterials. We also presented some majorshortcomings of BiVO4in the practical application and scheme out our researchproject. In this article, we prepared some bismuth vanadate nanomaterials withuniform particle size, rich morphology and composition by a simple solvent thermalsynthesis method.Some highlight results are as follows:In the first part,Monoclinic structured BiVO4nanoplates have been selectivelyprepared by a template-free and surfactant-free solvothermal process in an DMF/H2Omixed solvent. Monoclinic phase BiVO4photocatalyst with complex morphologiesnamely rodlike,sheetlike,flowerlike shapes,have been synthesized through controllingreaction conditions such as the reactant concentration, time, temperature, pH, solvents, the ratio of reactants.During this process, the presence of DMF and the volume ratioof DMF and water play important roles in the formation of the various morphologies.Interestingly, The morphologies of nanophase BiVO4can change with the ratio ofDMF/H2O from two-dimensional sheetlike structures to three-dimensional flowerlikestructures. And photocatalytic results show that BiVO4nanomaterials can photo-degrade efficiently the dye of rhodamine B.In the second part, we chose controlling morphologies and composition ofBiVO4composites by a doping method. Based on the theory of enhancingphotoefficiency, we used three schemes to synthesize the BiVO4semiconductornanomaterials with narrow particle size and tunable morphology by hydrothermalmethod. All samples were characterized by XRD and SEM, The results demonstratedthat some synthetic methods exerted a great effect on controlling the morphology andphase of BiVO4product. As the doped products, some as-prepared BiVO4compositesexhibited good photocatalytic activity in degradation of acid red B under naturalsunlight.