Highly Efficient and Stable Au/CeO2鈥揟iO2 Photocatalyst for Nitric Oxide Abatement: Potential Application in Flue Gas Treatment

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• 作者：Wei Zhu ; Shuning Xiao ; Dieqing Zhang ; Peijue Liu ; Hongjun Zhou ; Wenrui Dai ; Fanfan Liu ; Hexing Li
• 刊名：Langmuir
• 出版年：2015
• 出版时间：October 6, 2015
• 年：2015
• 卷：31
• 期：39
• 页码：10822-10830
• 全文大小：626K
• ISSN：1520-5827

文摘

In the present work, highly efficient and stable Au/CeO₂鈥揟iO₂ photocatalysts were prepared by a microwave-assisted solution approach. The Au/CeO₂鈥揟iO₂ composites with optimal molar ratio of Au/Ce/Ti of 0.004:0.1:1 delivered a remarkably high and stable NO conversion rate of 85% in a continuous flow reactor system under simulated solar light irradiation, which far exceeded the rate of 48% over pure TiO₂. The tiny Au nanocrystals (鈭?.1 nm) were well stabilized by CeO₂ via strong metal鈥搒upport bonding even it was subjected to calcinations at 550 掳C for 6 h. These Au nanocrystals served as the very active sites for activating the molecule of nitric oxide and reducing the transmission time of the photogenerated electrons to accelerate O₂ transforming to reactive oxygen species. Moreover, the Au鈥揅e³⁺ interface formed and served as an anchoring site of O₂ molecule. Then more adsorbed oxygen could react with photogenerated electrons on TiO₂ surfaces to produce more superoxide radicals for NO oxidation, resulting in the improved efficiency. Meanwhile, O₂ was also captured at the Au/TiO₂ perimeter site and the NO molecules on TiO₂ sites were initially delivered to the active perimeter site via diffusion on the TiO₂ surface, where they assisted O鈥揙 bond dissociation and reacted with oxygen at these perimeter sites. Therefore, these finite Au nanocrystals can consecutively expose active sites for oxidizing NO. These synergistic effects created an efficient and stable system for breaking down NO pollutants. Furthermore, the excellent antisintering property of the catalyst will allow them for the potential application in photocatalytic treatment of high-temperature flue gas from power plant.