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In situ controlled promotion of catalyst surfaces via NEMCA: The effect of Na on the Pt-catalyzed CO oxidation

Journal Article · · Journal of Catalysis; (United States)
;  [1]; ;  [2]
  1. Univ. of Patras (Greece)
  2. Univ. of Cambridge (United Kingdom)
It was found that the catalytic activity of Pt for CO oxidation can be markedly and reversibly affected by depositing polycrystalline Pt films on [beta][double prime]-Al[sub 2]O[sub 3], a Na[sup +] conductor, and applying external potentials to supply or remove Na to or from the Pt catalyst surface. The change in the rate of CO oxidation is typically 10[sup 3]-10[sup 5] times larger than the rate of supply or removal of Na. The use of the [beta][double prime]-Al[sub 2]O[sub 3] solid electrolyte supports permits precise in situ control of the Na coverage on the Pt surface. Sodium coverages of 0.02 cause up to 600% steady-state increase in the rate of CO oxidation under CO-rich conditions. The promoting effect is due to enhanced oxygen chemisorption on the Pt surface. Higher (>0.06) Na coverages poison the rate severely and reversibly due to the formation of a CO-Na-Pt surface complex. Rate oscillations can be reversibly induced or stopped and their frequency can be controlled by controlling the catalyst potential V[sub WR] and average work function e[Phi]. 46 refs., 12 figs., 1 tab.
OSTI ID:
6816401
Journal Information:
Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 146:1; ISSN 0021-9517; ISSN JCTLA5
Country of Publication:
United States
Language:
English