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CO 2 Methanation over Supported Ru/Al 2 O 3 Catalysts: Mechanistic Studies by In situ Infrared Spectroscopy
Author(s) -
Zheng Jian,
Wang Chengyang,
Chu Wei,
Zhou Yuanlin,
Köhler Klaus
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600651
Subject(s) - methanation , catalysis , adsorption , dissociation (chemistry) , ruthenium , ethylene glycol , carbon monoxide , inorganic chemistry , chemistry , infrared spectroscopy , ethylene , fourier transform infrared spectroscopy , in situ , materials science , chemical engineering , organic chemistry , engineering
Alumina supported ruthenium particles with an average diameter of 2 nm were prepared by a modified ethylene glycol reduction method. Catalytic methanation of CO 2 over this catalyst was studied by in situ FTIR spectroscopy. After pretreatment in H 2 , different types of adsorbed species were detected on the catalyst surface at 200 °C. Based on a series of targeted experiments under variation of gas composition, order of addition, reaction time and temperature, a reaction scheme and the rate‐determining steps of CO 2 methanation are proposed. Two potential reaction paths for the hydrogenation of CO 2 to form CH 4 were identified: (I) CO adsorbed on the Ru metal surface acted as active intermediate and the CO methanation followed. The dissociation of CO to form surface carbon represents the rate‐determining step. (II) Formyl species formed by hydrogenation of adsorbed CO 2 are the active intermediate and the formation of formyl was the rate‐determining step.