Highly crystalline bismuth vanadate (BiVO4) powder was prepared by a template-free hydrothermal method under different pH (~ 2, 3, 5, 8, 11) reaction conditions and characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, Brunauer–Emmett–Teller surface area, photoluminescence, and electron spin resonance techniques. It was found that variation in pH of the precursor solution can influence morphology, structure and, consequently, photocatalytic efficiency of obtained products. The spherical BiVO4 nanoparticles were obtained at pH 2 and 3, nanorods at pH 5 and 8, whereas nanoplates were obtained at pH 11. Among the different pH-based BiVO4 samples, the one prepared at pH ~ 11 (BiVO4-11) exhibited surface area 102.74 m2/g and degraded the dye solution completely within 90 min. Therefore, pH-controlled hydrothermal reaction can be useful to synthesize nanostructures with different morphologies efficiently for the enhanced photocatalytic degradation of pollutant under visible light.

中文翻译：

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从 BiVO4 的片状形态产生强氧化自由基用于在可见光下快速降解结晶紫染料

在不同pH（~2、3、5、8、11）反应条件下，通过无模板水热法制备高结晶钒酸铋（BiVO4）粉末，并通过X射线衍射、扫描电子显微镜、拉曼光谱、布鲁瑙尔进行表征–Emmett–Teller 表面积、光致发光和电子自旋共振技术。发现前体溶液的 pH 值变化会影响形态、结构，从而影响所得产物的光催化效率。在 pH 2 和 3 下获得球形 BiVO4 纳米颗粒，在 pH 5 和 8 下获得纳米棒，而在 pH 11 下获得纳米片。 在不同的基于 pH 的 BiVO4 样品中，在 pH ~ 11 (BiVO4-11) 下制备的样品显示出表面面积 102.74 m2/g 并在 90 分钟内完全降解染料溶液。所以，