Hierarchical bismuth oxyiodide(BiOI) microflower photocatalysts were synthesized by hydrolysis at room temperature. The concentration of ethylene glycol modulated the resulting BiOI morphology. The morphology, elemental composition, crystal phase structure, and absorption properties of the BiOI samples were characterized. Under visible light irradiation(k [ 400 nm), BiOI(S10) with a microflower morphology exhibited the highest photocatalytic activity in the degradation of methyl orange. The corresponding apparent pseudo-first-order rate constant was 0.826 h-1. The trend in photocatalytic activities of the prepared BiOI samples coincided with the trend in their photocurrents. A strategy for preparing hierarchical BiOI microflowers with good visible lightinduced photocatalytic activity is provided.
A new composite photocatalyst AgBr/BiOBr was prepared by loading AgBr on a BiOBr substrate via deposition-precipitation and characterized by X-ray diffraction,scanning electron microscopy,high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy.The as-prepared AgBr/BiOBr comprised face-centered cubic AgBr and tetragonal BiOBr particles.The average crystalline sizes of AgBr in the AgBr/BiOBr composites were less than 28.5 nm.The absorption edges of AgBr/BiOBr in visible-light region had a red shift with increasing AgBr content.Photocatalytic degradation of methyl orange results show that the AgBr/BiOBr composites could degrade methyl orange efficiently under visible-light irradiation (λ>420 nm).The optimal molar percentage of AgBr was 50 mol% with corresponding maximum k app of 0.00619 min -1.Active ·O 2- played a major role for methyl orange degradation while h + and ·OH had little effect on the photocatalytic process.The enhancement of photocatalytic activity of AgBr/BiOBr is mainly ascribed to the heterojunction effect between AgBr and BiOBr.
LIN HaiLi CAO Jing LUO BangDe XU BenYan CHEN ShiFu
