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The Dynamic Structure of Gold Supported on Ceria in the Liquid Phase Hydrogenation of Nitrobenzene
Author(s) -
Kartusch Christiane,
Makosch Martin,
Sá Jacinto,
Hungerbuehler Konrad,
van Bokhoven Jeroen A.
Publication year - 2012
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.201100187
Subject(s) - nitrobenzene , cationic polymerization , catalysis , chemistry , colloidal gold , phase (matter) , fourier transform infrared spectroscopy , photochemistry , spectroscopy , oxidation state , heterogeneous catalysis , inorganic chemistry , materials science , nanoparticle , chemical engineering , organic chemistry , nanotechnology , physics , quantum mechanics , engineering
With regard to heterogeneous catalysis by gold and, in particular, hydrogenation reactions, there is no consensus on the oxidation state of the catalytically active species. By means of high‐resolution X‐ray absorption spectroscopy, we determined in situ the oxidation state of gold in the functioning catalyst Au/CeO 2 in the slurry phase of the hydrogenation of nitrobenzene at high pressure. The conversion of nitrobenzene was monitored simultaneously by means of online attenuated total reflectance–Fourier transform infrared spectroscopy. We found that catalysts without measurable amounts of cationic gold were more active than catalysts with cationic gold. Any cationic gold that remained after pretreatment was reduced under reaction conditions, without any loss of activity. No evidence was found that the cationic gold contributed to the catalytic activity.