文献类型：期刊文献

英文题名：The relationship between the chemical state of Pd species and the catalytic activity for methane combustion on Pd/CeO2

作者：Ma, Jian[1];Lou, Yang[2];Cai, Yafeng[1];Zhao, Zhenyang[1];Wang, Li[1];Zhan, Wangcheng[1];Guo, Yanglong[1];Guo, Yun[1]

机构：[1]East China Univ Sci & Technol, Res Inst Ind Catalysis, Key Labs Adv Mat, Shanghai 200237, Peoples R China;[2]Arizona State Univ, Dept Phys, Tempe, AZ 85287 USA

年份：2018

卷号：8

期号：10

起止页码：2567

外文期刊名：CATALYSIS SCIENCE & TECHNOLOGY

收录：;EI(收录号：20182205262072);WOS:【SCI-EXPANDED(收录号:WOS:000435868200008)】；

基金：This project was supported financially by the National Key Research and Development Program of China (2016YFC0204300), the NSFC of China (21171055, 21571061), and the "Shu Guang" Project of the Shanghai Municipal Education Commission (12SG29).

语种：英文

外文关键词：Combustion - Nitrogen compounds - Catalyst activity - Palladium

摘要：Three Pd/CeO2 catalysts are synthesized by reduction-deposition and an impregnation method (IMP) to clarify how the chemical state of Pd influences the catalytic performance for CH4 combustion. The results show that Pd/CeO2 (HHA), using hydrazine hydrate as a reductant, shows much higher catalytic activity and stability for CH4 combustion than Pd/CeO2 (FA), using formaldehyde as a reductant, and Pd/CeO2 (IMP). The results of our comprehensive characterization reveal that there are two different chemical states of Pd species on Pd/CeO2 : Pd2+ in the form of PdO particles and Pd delta+ (2 < delta <= 4) in the form of PdxCe1-xO2, and the latter is mainly induced by the Pd species entering the lattice of CeO2, which acts as a transfer channel of active oxygen species from the CeO2 lattice to active Pd species. The activity of Pd/CeO2 directly correlates to the surface concentrations of PdO and adsorbed oxygen. An increase in the amount of PdxCe1-xO2 would thicken the transition layer and decrease the replenishment rate of oxygen vacancies through diffusion of lattice oxygen. Meanwhile, the existence of more PdxCe1-xO2 could promote the capture of produced CO2 on the CeO2 around Pd species and decrease the catalytic activity.