Cu-based Metal Oxide Catalysts For Simultaneous Catalytic Oxidation Of CO And NO In Sintering Flue Gas

Simultaneous catalytic oxidation of CO（Carbon monoxide）and NO（nitric oxide）in sintering flue gas is conducive to remove CO from flue gas,and efficiently convert NO into NO₂in order to enhance the subsequent rapid SCR reaction of flue gas.However,there are few studies on the simultaneous catalytic oxidation of CO and No.Therefore,Cu,Mn,Co,and Ce metals were selected to synthesize Cu-based composite metal oxide catalysts for the simultaneous catalytic oxidation of CO and NO in sintering flue gas in this study.The catalytic performance of the catalyst was tested by the activity evaluation experiment,the relationship between the properties and performance of the catalyst was analyzed through the characterization experiment,and the effect of O₂on the catalytic reaction and the related reaction principle were explored.This research is of great significance for the control of sintering flue gas pollution.The main results of this paper are as follows:（1）The supported Cu-M/TiO₂（M=Mn,Co,Ce）catalyst was synthesized by impregnation method.The CO catalytic oxidation test showed that the lowest temperature of 100%CO conversion was 240℃.After the CO pretreatment of catalyst,the CO conversions of the three catalysts reached 99%at 180°C.The simultaneous catalytic reaction test of Cu-M/TiO₂-CO on CO and NO showed that the catalytic performance decreased due to the presence of NO.Different reactions for NO occured on the catalyst,a small amount of CO-SCR reaction occured on the Cu-Ce/TiO₂;NO catalytic oxidation reaction occured on the Cu-Co/TiO₂and Cu-Mn/TiO₂.The CO-NO evaluation test under no oxygen conditions showed that the CO-SCR reaction occurred on the catalyst surface.（2）Different metal doping and CO pretreatment lead to the different degrees of redox effects in Cu-M/TiO₂which lead to the movement of species on the catalyst surface to low valence states,and the difference in the number of oxygen vacancies resulting in the difference of the catalytic performance among the catalysts.The presence of O₂had a significant impact on the CO-NO reaction on the catalyst.When O₂exists in the reaction system,it could occupy the surface oxygen vacancies of the catalyst,hindering the adsorption and dissociation of NO molecules.The CO-SCR reaction cannot occur effectively,and NO catalytic oxidation reaction occurs to produce NO₂.The presence of water vapor affected the catalyst,and H₂O molecules occupy the active sites on the surface of the catalyst,resulting in a decrease in the adsorption capacity of reactant molecules.（3）The bulk catalyst was prepared by co-precipitation method,which was used in the catalytic oxidation reaction of CO and NO.Cu₁Mn₂showed the best activity among binary catalysts（Cu₁M₂,M=Co,Mn,Ce）,reaching 99%CO conversion at 180°C.After Cu₁Mn₂was partially doped with Co and Ce,Cu₁Mn_1.8Ce_0.2exhibited higher catalytic activity,reaching 99%CO conversion at 150℃and 50%NO conversion at 190℃.Cu₁Mn₂had the strongest spinel active phase among binary catalysts,and the addition of Ce changed the phase structure and physical properties of the catalyst,and promotes the redox cycle on the catalyst surface and the generation of oxygen vacancies,increasing the catalytic activity.According to the characteristics of the catalysts,a combined system is designed in which NH₃is passed into the gas after the catalytic oxidation reaction of CO and NO for rapid SCR reaction,so as to realize the removal of CO and NO_x.