Growth And Photocatalytic Properties Of Ti-based Perovskite Oxides

ABO3(A = Ba,Sr,Pb)as a typical of perovskite-type oxides have been investigated intensively due to their wide applications in gas sensor,capacitors,actuators,photoelectrodes for dye-sensitized solar cells and photocatalyst.In this work,we report a self-template hydrothermal method for synthesis of ATiO3(A = Ba,Pb and Sr)perovskites using anatase TiO2 nanosheets as templates.Under hydrothermal condition,ATiO3 with different structure and morphology can be obtained.These samples were carefully characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)techniques and selected area electron diffraction(SAED),too.The growth mechanism of ATiO3 is explored by XRD evaluation over different reaction time,and it turns out that PbTiO3 grows most slowly among all the samples including BaTiO3,SrTiO3,BaxPb1-xTiO3 and SrxPb1-xTiO3.The diffusion of A site sources to the solid surface and the reaction at the solid/liquid interface could dominate the growth of ATiO3.All the as-prepared samples exhibit activities toward photocatalytic oxidation of NO in ppb level.In specific,PbTiO3 reveals the highest activity both under full spectrum and visible-light irradiation(λ>420 nm),whereas BaTiO3 exhibits the best selectivity for the formation of ionic species(NO3-),which could be ascribed to the different electronic structure and charge separation efficiency of ATiO3.Photocatalytic decomposition of water to hydrogen on all samples,the photocatalytic activity of the SrTiO3 is the best.After surface modification of CDs(graphene quantum dots),the photocatalytic reduction activities of SrTiO3 increased 30%.This study provides some important hints to tune the photocatalytic performances(activity and selectivity)of ATiO3 through the modification of A site elements.