Abstract The nanocomposites of ZnO/NiO loaded Multiwalled Carbon Nanotubes (MWNTs) were successfully fabricated using co-precipitation method. The synthesized photocatalyst were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) spectroscopy, Diffused reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FTIR) for the determination of crystal structure, morphology, elemental composition and optical properties respectively. The photocatalytic activity of as prepared photocatalyst was determined by monitoring the degradation of methyl orange (an azo dye) under ultra-violet (280 nm) and visible (480 nm) irradiation. The Diffuse reflectance spectra (DRS) exhibits absorbance tail around 400 nm, in the near UV region. SEM analysis shows the homogenous dispersion of ZnO and NiO on the surface of MWNTs. The efficiency for Photodegradation of ZnO coated MWNTs is shown to be greater than the efficiency of pristine ZnO. When NiO was loaded on the surface of MWNTs having ZnO coated layer, the activity was further enhanced and reached maximum for 3% NiO loading. The degradation in visible region is believed to be proceeding through self-sensitized degradation of pre-adsorbed dye. A different behavior for degradation was observed for ZnO coated MWNTs and ZnO/NiO coated MWNTs, which suggests that complete mineralization of azo dyes can be achieved in a self-sensitized degradation process after employing ZnO/NiO coated MWNTs.

中文翻译：

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用于纺织品染料降解的氧化锌/氧化镍涂层多壁碳纳米管

摘要 采用共沉淀法成功制备了ZnO/NiO负载多壁碳纳米管(MWNTs)的纳米复合材料。合成的光催化剂通过 X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、能量色散 X 射线 (EDX) 光谱、漫反射光谱 (DRS) 和傅里叶变换红外光谱 (FTIR) 对晶体进行了表征。分别为结构、形貌、元素组成和光学性质。通过在紫外线 (280 nm) 和可见光 (480 nm) 照射下监测甲基橙（偶氮染料）的降解来确定所制备的光催化剂的光催化活性。漫反射光谱 (DRS) 在 400 nm 附近显示出吸光尾，在近紫外区域。SEM 分析显示 ZnO 和 NiO 在 MWNT 表面上的均匀分散。ZnO 涂覆的 MWNT 的光降解效率显示出高于原始 ZnO 的效率。当 NiO 负载在具有 ZnO 涂层的 MWNT 表面时，活性进一步增强并在 3% NiO 负载时达到最大值。可见光区的降解被认为是通过预吸附染料的自敏降解进行的。对于 ZnO 包覆的 MWNT 和 ZnO/NiO 包覆的 MWNT，观察到了不同的降解行为，这表明在使用 ZnO/NiO 包覆的 MWNT 后，可以在自敏降解过程中实现偶氮染料的完全矿化。当 NiO 负载在具有 ZnO 涂层的 MWNT 表面时，活性进一步增强并在 3% NiO 负载时达到最大值。可见光区的降解被认为是通过预吸附染料的自敏降解进行的。对于 ZnO 包覆的 MWNT 和 ZnO/NiO 包覆的 MWNT，观察到了不同的降解行为，这表明在使用 ZnO/NiO 包覆的 MWNT 后，可以在自敏降解过程中实现偶氮染料的完全矿化。当 NiO 负载在具有 ZnO 涂层的 MWNT 表面时，活性进一步增强并在 3% NiO 负载时达到最大值。可见光区的降解被认为是通过预吸附染料的自敏降解进行的。对于 ZnO 包覆的 MWNT 和 ZnO/NiO 包覆的 MWNT，观察到了不同的降解行为，这表明在使用 ZnO/NiO 包覆的 MWNT 后，可以在自敏降解过程中实现偶氮染料的完全矿化。