Selective CO Methanation on Ru/TiO2 Catalysts: Role and Influence of Metal鈥揝upport Interactions

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• 作者：Ali M. Abdel-Mageed ; D. Widmann ; S. E. Olesen ; I. Chorkendorff ; J. Biskupek ; R. J. Behm
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：5
• 期：11
• 页码：6753-6763
• 全文大小：605K
• ISSN：2155-5435

文摘

Aiming at a detailed understanding of the role of metal鈥搒upport interactions in the selective methanation of CO in CO₂-rich reformate gases, we have investigated the catalytic performance of a set of Ru/TiO₂ catalysts with comparable Ru loading, Ru particle size, and TiO₂ phase composition but very different surface areas (ranging from 20 to 235 m² g^鈥?) in this reaction. The activity for CO methanation, under steady-state conditions, was found to strongly depend on the TiO₂ support surface area, increasing first with increasing surface area up to a maximum activity for the Ru/TiO₂ catalyst with a surface area of 121 m² g^鈥? and then decreasing for an even higher surface area; however, the selectivity is mainly determined by the Ru particle size, which slightly decreases with increasing support surface area. This goes along with an increase in selectivity for CO methanation, in agreement with a model proposed previously for nonreducible supports. In situ infrared measurements further revealed that also the adsorption properties for these catalysts, as evidenced by the CO adsorption strength, change significantly with increasing catalyst surface area and that strong metal鈥搒upport interactions cause a partial overgrowth of the Ru nanoparticles for the highest surface area catalyst. The interplay between catalyst surface area and reaction characteristics and the important role of metal鈥搒upport interactions in the reaction, in addition to particle size effects, will be elucidated and discussed.