Synthesis of high-performance Pd/Ce0.4Zr0.5La0.05Y0.05O1.95 catalysts for low-temperature methane combustion with the ultrasound-assisted field

Abstract

In this work, ultrasound-assisted sol–gel (UASG) and wet incipient impregnation (WIP) methods were employed to synthesize a series of Ce0.4Zr0.5La0.05Y0.05O1.95 oxygen storage materials (OSM) and Pd/Ce0.4Zr0.5La0.05Y0.05O1.95 catalysts under different frequency ultrasound external field. The effect of the ultrasonic external field on the low-temperature catalytic activity of the catalyst was investigated. The BET and TEM results demonstrated that ultrasound field can increase the catalyst's specific surface area by 25% and decrease the particle size from 10.1 nm to 7.3 nm. The XPS results showed that the concentrations of surface Pd2+, Oads, and Ce3+ species increased from 21%, 44%, and 43% to 42%, 65%, and 46%, respectively, enhancing the formation of Pd2+, Oads and Ce3+ species on the catalyst surface. The performance tests revealed that T90(CH4) of the prepared Pd/Ce0.4Zr0.5La0.05Y0.05O1.95 catalyst by UASG method decreased from 536 ℃ to 331 ℃, improving its low-temperature catalytic activity. Additionally, the catalysts synthesized using by UASG method exhibited the enhanced resistance to water and sulfur poisoning and maintained their catalytic performance for 20 h.