On the Effect of Preparation Methods of PdCe-MOR Catalysts as NO_x CH₄-SCR System for Natural Gas Vehicles Application

摘要

In the present work, the effect of several parameters involved in the preparation of PdCe-HMOR catalysts active for NO_x selective catalytic reduction with methane (NO_x CH₄-SCR) was studied. Results show that the catalytic performance of Pd-HMOR is better when palladium is introduced by ion-exchange, namely at room temperature. It was also shown that Pd loading does not influence the formation of cerium species, namely surface Ce4+ (CeO₂) species and CeO₂ species in interaction with Pd. However, when Ce is introduced before Pd, more surface CeO₂ species are stabilized in the support and less CeO₂ become in interaction with Pd, which results in a worse NO_x CH₄-SCR catalytic performance.