Structure and reactivity of PdO{sub x}/ZrO{sub 2} catalysts for methane oxidation at low temperatures
- Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering
- Univ. Nacional Autonoma, Ensenada (Mexico). Inst. of Physics
The kinetics of methane combustion at low temperatures are consistent with a Mars-van Krevelen redox mechanism involving the activation of methane on site pairs consisting of oxygen atoms and oxygen vacancies on the surface of PdO{sub x} crystallites. H{sub 2}O strongly inhibits methane oxidation rates by titrating surface vacancies in a quasi-equilibrated adsorption-desorption step. Initial activation periods during methane oxidation are related to the presence of oxygen-deficient PdO{sub x} crystallites, which contain stronger Pd-O oxygen bonds and increase their oxygen content during steady-state combustion reactions. Strong Pd-O bonds in small crystallites and in oxygen-deficient PdO{sub x} also lead to the observed decrease in methane oxidation turnover rates as crystallite size decreases or as samples are treated at temperatures above those required for PdO-to-Pd decomposition.
- OSTI ID:
- 289439
- Journal Information:
- Journal of Catalysis, Vol. 179, Issue 2; Other Information: PBD: 25 Oct 1998
- Country of Publication:
- United States
- Language:
- English
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