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采用便捷的涉及电沉积和退火过程的两步法在F掺杂的氧化锡基体上制备了高品质的多晶钒酸铋(BiVO4)薄膜,并运用扫描电镜、透射电镜、X射线衍射(XRD)、傅里叶变换红外光谱、紫外-可见光吸收光谱和拉曼光谱表征了所制薄膜的形貌和结构特征.XRD和光学分析结果表明,BiVO4薄膜为纯相的单斜白钨矿晶相结构.将该薄膜通过电化学(EC),光化学(PC)和光电化学(PEC)过程用于水溶液中氯酸离子的多相氧化反应中.采用紫外-可见吸附光谱仪监测氯酸盐浓度的降低.结果发现,在光的照射下采用PEC法时,BiVO4可有效催化氯酸盐的氧化.氯酸盐氧化反应级数为1级,PEC过程的反应速率常数明显高于EC和PC过程的.同时,提出了基于形成了高氯酸离子的催化氧化氯酸盐的反应机理.

A high-quality polycrystalline bismuth vanadate (BiVO4) film was prepared on a fluorine-doped tin oxide substrate via a facile two-step strategy involving electrodeposition and annealing processes.The morphology and structural characterization of the resulting film were investigated by different methods including scanning electron microscopy,transmission electron microscopy,X-ray diffraction (XRD),and Fourier transform infrared,ultraviolet-visible (UV-vis) absorption,and Raman spectroscopies.XRD patterns as well as optical measurements revealed that BiVO4 film crystallized with a pure monoclinic scheelite structure.The prepared BiVO4 film was used for heterogeneous oxidation of chlorate ions in aqueous solution via electrochemical (EC),photochemical (PC),and photoelectrochemical (PEC) processes.The decrease in concentration of chlorate was monitored using UV-vis absorption spectroscopy.The results revealed that BiVO4 could effectively perform chlorate oxidation under light irradiation through a PEC method.The kinetics of chlorate oxidation was consistent with a first-order reaction,and the rate constant for the PEC process was found to be much higher than those of EC and PC.Furthermore,a possible photocatalytic oxidation mechanism for chlorate mainly based on the formation of perchlorate ions is proposed.