Highly Efficient, Solar Active, and Reusable Photocatalyst: Zr-Loaded Ag鈥揨nO for Reactive Red 120 Dye Degradation with Synergistic Effect and Dye-Sensitized Mechanism

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• 作者：B. Subash ; B. Krishnakumar ; M. Swaminathan ; M. Shanthi
• 刊名：Langmuir
• 出版年：2013
• 出版时间：January 22, 2013
• 年：2013
• 卷：29
• 期：3
• 页码：939-949
• 全文大小：798K
• 年卷期：v.29,no.3(January 22, 2013)
• ISSN：1520-5827

文摘

The different wt % of Zr-codoped Ag鈥揨nO catalysts were prepared by the simple precipitation鈥搕hermal decomposition method and used for degradation of anionic azo dye Reactive Red 120 (RR 120) under natural sunlight. Highly efficient 4 wt % of Zr-codoped Ag鈥揨nO was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM) images, field emission scanning electron microscope (FE-SEM) images, energy-dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), and BET surface area measurements. Metal codopants increase the absorbance of ZnO to the entire visible region. XRD and XPS reveal that Ag is in the form of Ag⁰ and Zr in the form of Zr⁴⁺. The photocatalytic activity of 4 wt % Zr-codoped Ag鈥揨nO was compared with other single-metal-doped, undoped, and commercial catalysts. The quantum yields of all processes were determined and analyzed. Zr鈥揂g鈥揨nO was found to be more efficient than Ag鈥揨nO, Zr鈥揨nO, commercial ZnO, prepared ZnO, TiO₂鈥揚25, and TiO₂ at neutral pH for mineralization of RR 120 under solar light. To the best of our knowledge, this is the first report on the synthesis of Zr-codoped Ag鈥揨nO and its use in the degradation of RR 120 dye under natural sunlight illuminatioin. The influences of operational parameters such as the amount of photocatalyst, dye concentration, and initial pH on photomineralization of RR 120 have been analyzed. Mineralization of RR 120 has been confirmed by chemical oxygen demand (COD) measurements. A dual mechanism has been proposed for the higher efficiency of Zr鈥揂g鈥揨nO at neutral pH under solar light. This catalyst is found to be reusable.