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Flame‐Synthesized Ceria‐Supported Copper Dimers for Preferential Oxidation of CO
Author(s) -
Kydd Richard,
Teoh Wey Yang,
Wong Kenneth,
Wang Yong,
Scott Jason,
Zeng QingHua,
Yu AiBing,
Zou Jin,
Amal Rose
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200801211
Subject(s) - dimer , catalysis , materials science , copper , ionic bonding , oxygen , amorphous solid , selectivity , monomer , vacancy defect , phase (matter) , inorganic chemistry , photochemistry , chemical engineering , crystallography , ion , chemistry , organic chemistry , metallurgy , engineering , polymer , composite material
Rapid synthesis of CuCeO 2 catalysts by flame spray pyrolysis produces highly active Cu dimer morphologies without the need for additional catalyst pretreatment. The active Cu component is enriched onto the CeO 2 surface at concentrations higher than the nominal loading with no evidence of amorphous or crystalline CuO phase. Increasing the Cu content results in a morphological transition from isolated Cu monomers to oxygen‐bridged dimers and an associated increase in oxygen vacancy concentration. Dimer‐containing CuCeO 2 catalysts display high levels of activity and selectivity in the low‐temperature preferential oxidation of CO. Experimental measurements and simulations suggest that the geometry of the dimer presents a comparatively ionic CuO bond at the catalyst surface. Further studies indicate that these ionic dimer species promote preferential CO oxidation at lower temperatures than observed for monomeric Cu species. This is the first report to explicitly propose and demonstrate that the structural distortion associated with the formation of Cu dimers directly induces increased bond ionicity at the catalyst surface and that these changes are responsible for improved catalytic activity.