Mechanism study on CO-SCR over Ce-Co-Ox mixed oxides catalysts
FU Yu-xiu1, ZHONG Xue-mei1, CHANG Hua-zhen1, LI Jun-hua2
1. School of Environment & Natural Resource, Renmin University of China, Beijing 100872, China;
2. School of Environment, Tsinghua University, Beijing 100084, China
In this paper, a series of Ce-Co-Ox catalysts were prepared by co-precipitation method and the CO-SCR performance was studied. The influence of Co and Ce ratio on the activity of CO-SCR was investigated and the Ce(0.3)-Co(0.7)-Ox sample showed the highest NO conversion efficiency of 84% at 250℃. According to characterization results, it was proposed that the active sites for CO-SCR is Co in Ce(0.3)-Co(0.7)-Ox. There were two reasons responsible for the enhanced catalytic performance by Ce doping into the Ce-Co-Ox catalyst. Firstly, the specific surface area and adsorption capacity were increased with Ce doping. Secondly, a solid solution was formed in Ce-Co-Ox catalyst, resulting in the enhanced oxygen migration rate. In situ DRIFTs results suggested that the CO-SCR is likely to follow a mechanism that gaseous or weakly-adsorbed CO reacts with adsorbed NO species in the forms of bridging bidenate nitrite and chelate nitrate.
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