【摘要】 采用微波水热法,以BiVO₃·5H₂O和NH₄VO₃为原料,通过调控前驱液pH可控合成了不同晶体结构的可见光催化剂BiVO₄。利用X射线衍射（XRD）、紫外–可见漫反射（UV-Vis）、拉曼光谱（Raman）和场放射扫描电镜（SEM）等手段对所制备的样品进行了表征和分析,探讨了不同晶体结构BiVO₄的形成机理;同时以亚甲基蓝和一氧化氮为降解对象,考察了样品的光催化性能。结果表明,当前驱液pH为3～5时,制备的BiVO₄为四方锆石结构（z-t）,形貌为微米球;前驱液pH小于2或大于7时,制备的BiVO₄为单斜白钨矿结构（s-m）,形貌为多面体。这可能是由于前驱液pH的变化,致使前驱液中钒酸根离子和铋离子的存在形式发生了转变,进而影响BiVO₄的形成历程,使得BiVO₄样品的晶体结构、形貌、晶面裸露以及VO₄四面体等发生了改变。光催化试验结果表明, BiVO₄（s-m）光催化活性优于BiVO₄（s-t）。当前驱液pH为9时,制备的BiVO₄（s-m）样品由于结晶度高、（040）晶面暴露率高和VO₄四面体畸变程度大,表现出优异的光催化活性。更多还原

【Abstract】 Visible-light-driven photocatalyst BiVO₄ was synthesized via a facile microwave-hydrothermal method using BiVO3·5 H2 O and NH4 VO3 as raw materials. Crystal structure of BiVO₄ photocatalyst could be selectively controlled to be tetragonal or monoclinic by simply adjusting the pH of the precursor solution. The prepared sa mples were characterized by XRD, UV-Vis, Raman, and SEM. The mechanism of BiVO₄ formation with different crystal structures was discussed. Meanwhile, the photocatalytic performances of the prepared sample were evaluated by degradation of methylene blue and photocalytic oxidation of NO gas in air under visible light irr adiation. The results showed that BiVO₄（z-t） microsphere was obtained when the precursor pH is 3-5, but when the pH is less than 2 or greater than 7, the as-prepared powders are BiVO₄（s-m） with polyhedron morphology. This may be due to the change of pH that could form transformation of vanadate and bismuth ion in the precursor so lution, and then affect the formation process of BiVO₄, resuting in the change of crystal structure, morphology, crystal surface, and VO₄ tetrahedron of BiVO₄（s-m）. The photocatalytic tests indicated that the activity of BiVO₄（s-m） was much better than that of BiVO₄（z-t）. The BiVO₄（s-m） sample prepared at pH 9 exhibits excellent visible-light photocatalytic activity, because of its higher crystalline, preferentially exposed facts（040）, and higher degree distortion of VO₄^3- tetrahedron.更多还原