Abstract We report a study regarding the photocatalytic activity of urchin-like and needle-like ZnO nanostructures on methylene blue dye aqueous solutions under UV irradiation. Urchin-like and needle-like ZnO nanostructures were grown by thermal oxidation in air of commercial galvanized sheets. Oxidation temperatures were 300, 400, 500 and 600 °C; while oxidation time was fixed at 2 h. The structural and morphological features of the grown ZnO were studied by X-Ray Diffraction, Raman Spectroscopy and Scanning Electron Microscopy. Results show that polycrystalline ZnO is obtained at 400, 500 and 600 °C, while amorphous ZnO is produced at 300 °C. Structuring of the sample surface with different morphology was obtained for the oxidation temperatures applied; urchin-like and needle-like nanostructures were obtained at 500 and 600 °C, respectively. Photocatalytic results show that both crystallinity and morphology of the as-prepared ZnO are very important for the photocatalytic activity. In view of the results hereby presented, these urchin-like and needle-like nanostructures could potentially be implemented in water cleaning at industrial level.

中文翻译：

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热氧化合成光催化海胆状和针状ZnO纳米结构

摘要 我们报告了在紫外线照射下海胆状和针状 ZnO 纳米结构对亚甲蓝染料水溶液的光催化活性的研究。海胆状和针状 ZnO 纳米结构是通过热氧化在商业镀锌板的空气中生长的。氧化温度分别为300、400、500和600℃；而氧化时间固定为2小时。通过 X 射线衍射、拉曼光谱和扫描电子显微镜研究了生长的 ZnO 的结构和形态特征。结果表明，多晶 ZnO 在 400、500 和 600 °C 下获得，而无定形 ZnO 在 300 °C 下获得。对于所施加的氧化温度，获得了具有不同形态的样品表面结构；分别在 500 和 600 °C 下获得了海胆状和针状纳米结构。光催化结果表明，所制备的 ZnO 的结晶度和形貌对光催化活性非常重要。鉴于本文提出的结果，这些海胆状和针状纳米结构有可能在工业水平的水净化中实施。