Pd/Al2O3 catalysts modified with Mg for catalytic combustion of methane: Effect of Mg/Al mole ratios on the supports and active PdOx formation

Pd/Al2O3 catalysts modified by different amount of magnesium were fabricated for catalytic combustion of methane (CCM). After the introduction of different amount of magnesium, Al2O3, MgAl2O4-like mixed oxide and Mg(Al)Ox solid solution were formed. Owing to the formation of distinguished supports, the supported Pd species, i.e. metallic Pd, PdOx and support-Pd oxide complex were formed, and they were quite different in relative content and Pd↔PdO transformation ability. It was found that PdOx was active at low temperature, while metallic Pd particles and support-Pd oxide complex were active at high reaction temperature. The one with Mg/Al mole ratio of 1:3 was the most easily in Pd↔PdO transformation, demonstrating the best catalytic activity towards CCM reaction. © 2019, Science Press. All right reserved.