Three-Dimensional Ordered Mesoporous MnO2-Supported Ag Nanoparticles for Catalytic Removal of Formaldehyde

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• 作者：Bingyang Bai ; Qi Qiao ; Hamidreza Arandiyan ; Junhua Li ; Jiming Hao
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：March 1, 2016
• 年：2016
• 卷：50
• 期：5
• 页码：2635-2640
• 全文大小：407K
• ISSN：1520-5851

文摘

Three-dimensional (3D) ordered mesoporous Ag/MnO₂ catalyst was prepared by impregnation method based on 3D-MnO₂ and used for catalytic oxidation of HCHO. Ag nanoparticles are uniformly distributed on the polycrystalline wall of 3D-MnO₂. The addition of Ag does not change the 3D ordered mesoporous structure of the Ag/MnO₂, but does reduce the pore size and surface area. Ag nanoparticles provide sufficient active site for the oxidation reaction of HCHO, and Ag (111) crystal facets in the Ag/MnO₂ are active faces. The 8.9% Ag/MnO₂ catalyst shows a higher normalized rate (10.1 nmol·s^–1·m^–2 at 110 °C) and TOF (0.007 s^–1 at 110 °C) under 1300 ppm of HCHO and 150 000 h^–1 of GHSV, and its apparent activation energy of the reaction is the lowest (39.1 kJ/mol). More Ag active sites, higher low-temperature reducibility, more abundant surface lattice oxygen species, oxygen vacancies, and lattice defects generated from interaction Ag with MnO₂ are responsible for the excellent catalytic performance of HCHO oxidation on the 8.9% Ag/MnO₂ catalyst. The 8.9% Ag/MnO₂ catalyst remained highly active and stable under space velocity increasing from 60 000 to 150 000 h^–1, under initial HCHO concentration increasing from 500 to 1300 ppm, and under the presence of humidity, respectively.