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Autori: Ciuparu D, Pfefferle L
Editorial: Applied Catalysis A: General, 209, p.415 - 428, 2001.
The effect of the support (gamma -alumina and zirconia) and of the presence of water on the catalytic activity of palladium particles was investigated both on oxidized and reduced states using temperature programmed reaction (TPR). The support was found to influence the onset and the rate of the reoxidation process. The particle size of the palladium phase, however, strongly influenced the reduction temperature and the activity decay and recovery during TPR experiments. In the metallic form, the catalyst is not affected by the water presence; in oxide state we found that, independent of the support, the inhibitory effect of the water molecules is stronger at lower temperatures. Consequently, the reaction may take place in two different regimes: one in which the rate limiting step is water desorption from the catalyst surface, which is favored by low temperatures (<500
Cuvinte cheie: palladium catalysts, methane combustion, support effects, water inhibition, kinetics