Preparation, Characterization, and Kinetic Study of a Core鈥揝hell Mn3O4@SiO2 Nanostructure Catalyst for CO Oxidation

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• 作者：Jing Xu ; Ya-Qing Deng ; Xiao-Man Zhang ; Yan Luo ; Wei Mao ; Xue-Jing Yang ; Like Ouyang ; Pengfei Tian ; Yi-Fan Han
• 刊名：ACS Catalysis
• 出版年：2014
• 出版时间：November 7, 2014
• 年：2014
• 卷：4
• 期：11
• 页码：4106-4115
• 全文大小：599K
• ISSN：2155-5435

文摘

Mn₃O₄@SiO₂ prepared via a St枚ber route showed a steady reaction rate for CO oxidation at 250 掳C after 12 h. The reaction orders, with respect to CO (0.49鈥?.12) and O₂ (0.4鈥?.6), were obtained for a Mn₃O₄@SiO₂ catalyst (d_Mn3O4 = 7.6 nm) in the temperature range of 220鈥?80 掳C. Via Operando Raman spectroscopy, a CO_ad-induced change in the symmetric stretch of Mn鈥揙鈥揗n (from 636 cm^鈥? to 642 cm^鈥?) was observed for Mn₃O₄@SiO₂, indicating a tiny structure modification of core Mn₃O₄ by the adsorption of CO. With the combination of the catalyst structure and the kinetics of CO oxidation, we assume that this reaction proceeds mainly through the Langmuir鈥揌inshelwood mechanism at or below 280 掳C. In comparison with the reference 伪-Mn₂O₃ catalyst, the presence of shell SiO₂ does not change the reaction behavior but improves the catalyst stability.

Keywords:

Mn₃O₄@SiO₂; nanostructure catalysts; Operando Raman spectroscopy; kinetics; CO oxidation