Study on Stability of AgI/TiO₂ Visible Light Photocatalysts in Solutions of Various pH Values

Abstract:

Nanostructured AgI/TiO₂ photocatalysts exhibit highly efficient visible light photocatalytic activity. Though there have been extensive investigations on AgI/TiO₂ photocatalysts, study on their stablity is still very limited. So in this paper, such a study is designed and conducted. AgI/TiO₂ nanostructured photocatalysts were prepared and separately immersed in HCl solutions, DI water and NaOH solutions with pH value of 0, 4, 7, 10 and 14, respectively. X-ray diffraction and diffusive reflectance UV-vis spectroscopy analyses reveal that the immersion in acidic solutions led to the formation of AgCl and a blue shifting to 450nm for the absorption edge of AgI/TiO₂, while the alkaline treatment had no significant effect on the composite structure of AgI/TiO₂ or on the UV-vis absorption edge. Photocatalytic tests show that immersion in acidic solutions had more significant influence on AgI/TiO₂ photocatalytic degradation of methyl orange (MO). At pH = 4, photocatalytic efficiency was dropped nearly 30%. At pH = 10, no significant change was observed. AgI/TiO₂ nanostructured photocatalysts have thus been found to display a higher stability in alkaline solutions than in acidic solutions.

• Periodical: Advanced Materials Research (Volumes 399-401)
• Pages: 1272-1275
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.399-401.1272
• Online since: November 2011
• Authors: Lu Feng, Ke Feng He, Wan Ping Chen
• Keywords: AgI/TiO₂, pH, Photocatalyst, Stability

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