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Influence of Coordination Environment of Anchored Single‐Site Cobalt Catalyst on CO 2 Hydrogenation
Author(s) -
Jimenez Juan D.,
Wen Cun,
Royko Michael M.,
Kropf Arthur J.,
Segre Carlo,
Lauterbach Jochen
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201901676
Subject(s) - cobalt , catalysis , xanes , extended x ray absorption fine structure , x ray photoelectron spectroscopy , methanation , transition metal , heterogeneous catalysis , chemistry , coordination number , inorganic chemistry , materials science , absorption spectroscopy , crystallography , photochemistry , spectroscopy , chemical engineering , organic chemistry , physics , quantum mechanics , engineering , ion
Heterogeneous catalysts generally have a variety of active‐site structures due to the innate heterogeneity of the surface, resulting in complicated correlations between activity and active‐site structure. Single site heterogeneous cobalt catalysts with a uniform catalytic surface were utilized as a platform to probe surface sensitive reactions; in this case CO 2 hydrogenation. It was found that atomically isolated cobalt single sites, which exist solely in the tetrahedral Co 2+ coordination, exclusively form CO under typical CO 2 methanation conditions, while cobalt clusters yielded the highest rate of CO 2 reaction and began to form methane. Utilizing the principles of Ostwald Ripening to probe the ensemble effects for CO 2 hydrogenation, the transition from atomic isolation to small clusters of atoms to nanoparticles was explored. The chemical structure of the cobalt was elucidated primarily via X‐Ray Absorption Spectroscopy (XANES/EXAFS) and X‐Ray Photoelectron Spectroscopy (XPS).