Combined temperature-programmed reaction and in-situ x-ray scattering studies of size-selected silver clusters under realistic reaction conditions in the epoxidation of propene.
The catalytic activity and dynamical shape changes in size-selected nanoclusters at work are studied under realistic reaction conditions by using a combination of simultaneous temperature-programmed reaction with in situ grazing-incidence small angle x-ray scattering. This approach allows drawing a direct correlation between nanocatalyst size, composition, shape, and its function under realistic reaction conditions for the first time. The approach is illustrated in a chemical industry highly relevant selective partial oxidation of propene on a monodisperse silver nanocatalyst. The shape of the catalyst undergoes rapid change already at room temperature upon the exposure to the reactants, followed by a complex evolution of shape with increasing temperature. Acrolein formation is observed around 50 C while the formation of the propylene oxide exhibits a sharp onset at 80 C and is leveling off at 150 C. At lower temperatures acrolein is produced preferentially to propylene oxide; at temperatures above 100 C propylene oxide is favored.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Air Force Office fo Scientific Research; German Research Foundation (DFG); German Science Foundation
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 966671
- Report Number(s):
- ANL/CSE/JA-64094; JCPSA6; TRN: US200921%%534
- Journal Information:
- J. Chem. Phys., Vol. 131, Issue Sep. 28, 2009; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- ENGLISH
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