CO oxidation over CuO/Ce1-xCuxO2-δ and Ce1-xCuxO2-δ catalysts: Synergetic effects and kinetic study
CO oxidation over CuO/Ce1-xCuxO2-δ and Ce1-xCuxO2-δ catalysts: Synergetic effects and kinetic study
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DOI：
10.1016/j.jcat.2012.02.010
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发表时间：
2012-05-01
影响因子：
7.3
通讯作者：
Luo, Meng-Fei
中科院分区：
文献类型：
--
作者：
Jia, Ai-Ping;Hu, Geng-Shen;Luo, Meng-Fei
制备了一系列CuO/Ce 1-xCuxO 2-delta催化剂，并经硝酸处理得到相应的Ce 1-xCuxO 2-delta催化剂。X射线衍射和拉曼光谱结果表明，催化剂表面存在CuO物种和Ce 1-xCuxO 2-δ固溶体。CO氧化实验发现，CO转化率与CuO/Ce 1-xCuxO 2-delta催化剂中CO的化学吸附浓度和氧空位浓度成正比，表明表面CuO物种和CuxCe 1-xO 2-delta固溶体对反应活性的协同作用，前者为CO的化学吸附提供了位点，后者促进了催化剂的氧活化还原。动力学研究表明，CuO/Ce 1-xCuxO 2-delta和CeCe 1-xCuxO 2-delta的表观活化能分别为42 kJ mol（-1）和95 kJ mol（-1）。CuO/Ce 1-xCuxO 2-delta催化剂的反应速率为r（CO）= k（1）P（CO）（0.74）P（O2）（0），Ce 1-xCuxO 2-delta催化剂的反应速率为r（CO）= k（2）P（CO）（1.04）P（O2）（0），表明反应遵循Mars-van Krevelen型机理。(C)2012 Elsevier Inc. All rights reserved.
A series of CuO/Ce1-xCuxO2-delta catalysts were prepared, and corresponding Ce1-xCuxO2-delta catalysts were obtained with nitric acid treatment. X-ray diffraction and Raman spectroscopic results revealed the presence of surface CuO species and Ce1-xCuxO2-delta solid solution in the catalysts. CO oxidation testing found that the CO conversion was proportional to the concentrations of chemisorbed CO and oxygen vacancies in the CuO/Ce1-xCuxO2-delta catalysts, suggesting synergetic effects of the surface CuO species and CuxCe1-xO2-delta solid solution on the reactivity, as the former provided sites for CO chemisorption and the latter promoted reducibility of the catalyst for oxygen activation. Kinetic studies showed that the apparent activation energy was 42 kJ mol(-1) for CuO/Ce1-xCuxO2-delta and 95 kJ mol(-1) for CeCe1-xCuxO2-delta. The power-law rate expression was r(CO) = k(1)P(CO)(0.74)P(O2)(0) for CuO/Ce1-xCuxO2-delta and r(CO) = k(2)P(CO)(1.04)P(O2)(0), for the Ce1-xCuxO2-delta catalyst, indicating that the reaction pathway followed a Mars-van Krevelen type mechanism. (C) 2012 Elsevier Inc. All rights reserved.