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In situ controlled promotion of Pt for CO oxidation via NEMCA using CaF{sub 2} as the solid electrolyte

Journal Article · · Journal of Catalysis
OSTI ID:110993
During the past 6 years, the effect of non-Faradaic electrochemical modification of catalytic activity (NEMCA) or in situ controlled promotion of catalyst surfaces has been described for over 25 catalytic reactions on Pt, Pd, Rh, Ag, and Ni surfaces using O{sup 2-}-conducting solid electrolytes, such as yttria-stabilized zirconia (YSZ), Na{sup +}-conducting solid electrolytes, such as {beta}-Al{sub 2}O{sub 3} and H{sup +}-conducting solid electrolytes such as CsHSO{sub 4} as the active catalyst support. In these studies, the porous catalyst film also serves as an electrode in a galvanic cell of the type gaseous reactants, metal catalyst/solid electrolyte/metal, O{sub 2} and the NEMCA effect is induced by applying currents or potentials (-2 to +2 V) between the metal catalyst and the metal counter electrode. The induced change in catalytic rate on the catalyst film can be up to 3 x 10{sup 5} times higher than the rate of ion supply and up to 100 times higher than the catalytic rate when no voltage is applied. Significant modification in product selectivity have also been demonstrated. When using {beta}{double_prime}-Al{sub 2}O{sub 3} as the solid electrolyte, NEMCA is due to the promoting action of spillover Na{sup {delta}}, while in the case of YSZ, NEMCA is due to the promoting action of spillover oxide ions O{sup {delta}}- as recently confirmed by XPS. 17 refs., 4 figs.
OSTI ID:
110993
Journal Information:
Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 149; ISSN 0021-9517; ISSN JCTLA5
Country of Publication:
United States
Language:
English