Study On The Influence Of Rare Earth Elements On Catalutic Performance Of Cu/Sepiolite

Natural sepiolite was modified by acid and used as the support. Then active promoters copper was loaded. The performance of Cu/Sep catalyst for catalytic oxidation of CO and catalytic reduction of NOx was studied. And influence of adding rare earth element La,Sm,Ce and Pr on activity of the catalyst also was studied. The catalytic activity for CO oxidation was evaluated by gas chromatogram and Oxides of Nitrogen Analyzer evaluated the catalytic activity for NOx reduction. XRD,BET,SEM and XRD were applied to characterize the catalysts.The experiment results show that after sepiolite was modified by hydrochloric acid and nitric acid respectively, Cu/Sep could make the conversion of CO reach 100% at about 180℃. The addition of 0.5%⁵% rare earth elements La,Sm,Ce and Pr to Cu/Sep catalysts had no obvious influence on the reaction of CO oxidation.Cu/Sep had a certain active for NOx reduction. The highest conversion of NOx was 17% in about 310℃. It is necessary to add rare earth elements on Cu/Sep for NOx reduction. The addition of 1%⁵% rare earth elements to Cu/Sep catalysts could improve the reaction of NOx reduction obviously. The highest conversion of NOx could improve from 20% to 50%. The 2% loading of Ce was propriety on Cu/Sep. When Ce and La were impregnated orderly and their proportion was 5:1 on catalysts, Cu/Sep could make the highest conversion of NOx reach 28%. When C3H6 was used reducer, Cu/Sep had lower active temperature and higher active for NOx reduction. The active temperature could decrease about 90℃and the conversion of NOx could improve 50%. So C3H6 was the appropriate reducer for NOx reduction in the experiments.From XRD,BET,SEM and XPS results, it was found that the oxidized form of rare earths was La₂O₃,Sm₂O₃,CeO₂ and PrO₂ on the Cu/Sep. The special surface area and pore distribution of sepiolite had no large difference between different acid modification methods. Large particles dispersed more equably in the SEM pictures of Re-Cu/Sep than in that of Cu/Sep. This showed that rare earth was a good dispersant to activity components. After the rare earth element Ce was added into Cu/Sep, the binding energy of Cu2p3 decreased from 934.1ev to 933.0ev. It showed that reductive Cu species increased in the surface of Cu/Sep and the catalytic activity of Cu/Sep could improve.This study were not only enriching the material of catalyst for NOx reduction and CO oxidation but also providing a reference to the technology of adding rare earth as the promoter into Cu/Sep catalysts.