Abstract This paper deals with the relationship between photocatalysis and photo-generated hydrophilicity under UV light irradiation of ZnO/ZnCr2O4 nanocomposite film prepared via spray pyrolysis method. XRD investigations indicate that the nanocomposite sample show the presence of wurtzite ZnO phase having crystallites oriented preferentially along c-axis with the presence of a secondary phase spinel of ZnCr2O4. Indeed, a special emphasis has been focused on the photoluminescence study of such nanocomposite film which point out the considerable role of the surface and bulk defects in this nanocomposite. Consequently, the synergistic effect between ZnO and ZnCr2O4 has a notable beneficial effect on photocatalytic activity improving as well as hydrophobic to hydrophilic transition under UV light irradiation which may be attributed to the active surface area, the adsorption of the dye as well as efficient electron-hole charge separation and transfer at the interfaces of ZnO/ZnCr2O4 nanocomposite allowing the enhanced hydroxyl and superoxide radicals production. Such important contribution of radicals was confirmed experimentally when using scavengers in the photocatalytic reaction.

中文翻译：

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紫外光照射下亚甲蓝在 ZnO/ZnCr2O4 纳米复合材料上的光催化降解和光生亲水性

摘要 本文研究了喷雾热解法制备的ZnO/ZnCr2O4纳米复合薄膜在紫外光照射下的光催化作用与光生亲水性之间的关系。XRD 研究表明，纳米复合材料样品显示出纤锌矿ZnO 相的存在，其微晶优先沿c 轴取向，同时存在ZnCr 2 O 4 的第二相尖晶石。事实上，特别强调了这种纳米复合膜的光致发光研究，它指出了表面和体缺陷在这种纳米复合材料中的重要作用。最后，ZnO 和 ZnCr2O4 之间的协同效应对提高光催化活性以及在紫外光照射下疏水到亲水的转变具有显着的有益效果，这可能归因于活性表面积、染料的吸附以及有效的电子空穴电荷在 ZnO/ZnCr2O4 纳米复合材料的界面处分离和转移，从而增强羟基和超氧自由基的产生。当在光催化反应中使用清除剂时，实验证实了自由基的这种重要贡献。