Mesoporous Co₃O₄-supported gold nanocatalysts: Highly active for the oxidation of carbon monoxide, benzene, toluene, and o-xylene

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• 作者：Yuxi Liu ; Hongxing Dai ; Jiguang Deng ; Shaohua Xie ; Huanggen Yang ; Wei Tan ; Wen Han ; Yang Jiang ; Guangsheng Guo
• 关键词：Three-dimensionally ordered mesoporous cobalt oxide ; Supported gold catalyst ; Carbon monoxide oxidation ; Volatile organic compound oxidation
• 刊名：Journal of Catalysis
• 出版年：January, 2014
• 年：2014
• 卷：309
• 期：Complete
• 页码：408-418
• 全文大小：2519 K

文摘

Three-dimensionally ordered mesoporous Co₃O₄ (meso-Co₃O₄) and its supported gold (xAu/meso-Co₃O₄, x = 3.7-9.0 wt%) nanocatalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected colloidal deposition methods, respectively. The meso-Co₃O₄ and xAu/meso-Co₃O₄ samples exhibited a high surface area of 91-94 m²/g. The Au nanoparticles with a size of 1-5 nm were uniformly deposited inside the mesoporous channels of meso-Co₃O₄. There were good correlations of oxygen adspecies concentration and low-temperature reducibility with catalytic activity of the sample for CO or BTX (benzene, toluene, and o-xylene) oxidation. Among meso-Co₃O₄ and xAu/meso-Co₃O₄, the 6.5Au/meso-Co₃O₄ sample performed the best, giving the T_90% (the temperature required for achieving a CO or BTX conversion of 90%) of 鈭?5, 189, 138, and 162 掳C for the oxidation of CO, benzene, toluene, and o-xylene, respectively. The apparent activation energies (23 and 45-55 kJ/mol) over 6.5Au/meso-Co₃O₄ were much lower than those (48 and 72-92 kJ/mol) over bulk Co₃O₄ for CO and BTX oxidation, respectively. The effects of water vapor, carbon dioxide, and sulfur dioxide on the catalytic activity of the 6.5Au/meso-Co₃O₄ sample were also examined. It is concluded that the higher surface area and oxygen adspecies concentration, better low-temperature reducibility, and strong interaction between Au and meso-Co₃O₄ were responsible for the excellent catalytic performance of 6.5Au/meso-Co₃O₄.