Photocatalytic reduction of 4-nitrophenol with arginine-modified titanium dioxide nanoparticles

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• 作者：Won-Young Ahn ; Sarah A. Sheeley ; Tijana Rajh ; Donald M. Cropek
• 关键词：Photocatalysis ; Nitrophenol ; Surface-modified titanium dioxide
• 刊名：Applied Catalysis B: Environmental
• 出版年：2007
• 出版时间：18 June 2007
• 年：2007
• 卷：74
• 期：1-2
• 页码：103-110
• 全文大小：1310 K

文摘

The surface charge of titanium dioxide (TiO₂) affects the adsorption rates of target molecules, thereby influencing the associated photocatalytic degradation rates of these molecules. This study describes the specific photocatalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with arginine-modified TiO₂ (Arg–TiO₂) nanoparticles. 4-AP was the only identifiable by-product detected by chromatographic analysis. The terminal amine groups of the arginine monolayer create a positive TiO₂ surface charge over a wide range of pH values. At high pH, the degradation rate of 4-NP increased due to improved target adsorption. Furthermore, the presence of the arginine monolayer perturbs the degradation mechanism distribution of 4-NP away from indiscriminant oxidation toward selective reduction. Photocatalysis of a target molecule such as benzenesulfonic acid (BSA) showed that while electrostatic attraction of the target to the photocatalyst is important, the reduction potential of the target molecule dictates efficient degradation on Arg–TiO₂.