A highly efficient visible-light-driven novel p-n junction Fe2O3/BiOI photocatalyst: Surface decoration of BiOI nanosheets with Fe2O3 nanoparticles

Abstract

Novel xFe2O3/yBiOI composites (x/y=0.25, 0.35, 0.45 molar ratios) with a p-n heterojunction were prepared for the first time through an in situ hydrolysis method under solvothermal conditions. The phase structure, morphology and optical properties of the composites were studied using several characterization tools including X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Fourier transform infrared (FTIR), N2 adsorption-desorption isotherms (BET) and UV–vis diffuse reflectance spectroscopy (UV-DRS). The characterization results suggest square shaped nanosheets of BiOI with Fe2O3 nanoparticles well distributed on the surface of BiOI nanosheets. The photodegradation performances of the xFe/yBi samples were investigated using aqueous solution of Rhodamine B (RhB) dye. The xFe/yBi composites displayed much higher photocatalytic efficiencies for RhB degradation than the single BiOI under visible light (λ>400nm). Specifically, the degradation rate of xFe/yBi samples at molar ratio of 0.35 is 4.24 times higher than single BiOI. The novel Fe2O3/BiOI heterojunction was found to be highly stable in cyclic experiments. Based on the results of BET, PL and DRS analysis, the enhanced photocatalytic efficiency can be mainly ascribed to the formation of stable p-n heterojunction between Fe2O3 and BiOI, which facilitates the transfer and separation of photogenerated electron-hole pairs.