Regeneration of S-poisoned Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts for the combustion of methane

摘要

This work investigates the regeneration of S-poisoned Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts under different CH_4 containing atmospheres. Under lean combustion conditions in the presence of excess O_2, partial regeneration took place for both systems only above 750 °C after decomposition of stable sulphate species adsorbed on the support. Under alternate lean combustion/CH_4-reducing pulse regeneration is markedly anticipated down to 550-600 °C. Experiments evidenced an effective role of ceria in preventing PdO from sulphation and in promoting regeneration via sulphates decomposition under reducing conditions.