Dynamic studies of CO oxidation on nanoporous Au using a TAP reactor

• Published in: Journal of catalysis 2011-03, Vol.278 (2), p.219-227
• Main Authors: Wang, L.C., Jin, H.J., Widmann, D., Weissmüller, J., Behm, R.J.
• Format: Article
• Language: English
• Subjects: ambient temperature; atmospheric pressure; carbon dioxide; Carbon monoxide; Catalysis; catalysts; Chemistry; CO oxidation; Colloidal state and disperse state; detection limit; Dynamic studies; Exact sciences and technology; General and physical chemistry; gold; Kinetics; Nanoporous Au catalysts; Oxidation; Oxygen; Oxygen storage capacity (OSC); Porous materials; probability; streams; Temporal analysis of products (TAP); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2010.12.007

The oxidation of CO on nanoporous Au, in particular the activation of molecular O 2, was investigated by a combination of kinetic and TAP measurements, showing the formation of stable adsorbed active oxygen via dissociative O 2 adsorption. [Display omitted] ► Mechanism of oxygen activation and CO oxidation on nanoporous Au (NPG). ► Oxygen is activated at 30 °C on NPG, forming a stable atomically adsorbed species. ► Oxygen activation depends non-linearly on the O 2 partial pressure. ► O 2 activation/stable O act formation is rate limiting for continuous CO oxidation. The oxidation of CO on nanoporous Au (NPG), in particular the activation of molecular O 2, was investigated by a combination of kinetic and temporal analysis of products (TAP) measurements. Continuous reaction measurements in a flow of reaction gas, at atmospheric pressure, show a catalytic behavior of the NPG, with the activity decreasing to 33% of the initial activity over 1000 min on stream. In contrast, during simultaneous pulsing of CO and O 2, the formation of CO 2 on the NPG catalyst rapidly decreased to values below the detection limit after reactive removal of the surface oxygen species present after sample preparation. Possible mechanisms explaining this discrepancy are discussed, using further information from multi-pulse TAP experiments, which revealed that molecular O 2 can be activated and stored on NPG catalyst at room temperature, though with a low probability.