Preparation Of Cerium-supported Cu-based Oxide Catalyst And CO-SCR Performance Research

CO selective catalytic removal of NO_x（CO-SCR）process has become a highly attractive and promising flue gas denitrification technology because of its synergistic removal of multiple pollutants and reduction of industrial costs.The development of suitable catalysts is a decisive factor for the optimal efficiency of the process.Environmentally friendly copper oxide is considered as a potential CO-SCR denitrification catalyst due to its suitable oxidation-reducing properties.However,its easy sintering at high temperature and poor dispersity become the key limiting factors for its application.The coordination of copper oxide and suitable support can disperse copper species,overcome their existing defects,and improve the catalytic activity.Based on this,in order to realize the full play of the catalytic potential of copper oxide CO-SCR,this paper intends to optimize the carrier to improve the catalytic activity,N₂selectivity and resistance to O₂/H₂O/SO₂ of copper-supported oxide catalyst in CO-SCR reaction.XPS,NO-TPD,H₂-TPR,In situ DRIFTs and other series of characterization were used to obtain the structural characteristics of the constructed catalyst,and the internal correlation between the physical and chemical properties of the catalyst and the CO-SCR performance was clarified,providing a theoretical basis for the construction of Cu-based CO-SCR denitrification catalyst with potential industrial application.The specific research contents and conclusions are as follows:（1）The effect of reducible supports on the denitrification performance of Cu-based supported oxide catalysts was investigated.The reducible oxides（Ce O₂ andγ-Fe₂O₃）were selected as the supports,and Cu O_x/Ce O₂ and Cu O_x/γ-Fe₂O₃ were prepared by impregnation method with a load of 2.5wt%.At the same time,the influence of reducible support on the physical and chemical properties of Cu-based catalyst and the denitrification performance of CO-SCR were systematically studied by using Cu O as reference catalyst.The results showed that the introduction of reducible supports improved the catalytic activity of copper oxides to varying degrees,and the cerium-supported Cu-based catalyst（Cu O_x/Ce O₂）with Ce O₂ as the support showed better SCR catalytic activity,higher N₂ selectivity and wider activity temperature window.（2）Design and construct cerium-supported Cu-based oxide catalysts（Cu O_x/Ce O₂-H,Cu O_x/Ce O₂-T,Cu O_x/Ce O₂-C and Cu O_x/Ce O₂-F）with different microstructure（morphology&crystal plane）.The effects of the microstructure of Ce O₂ on the microstructure and physical&chemical properties of cerium-supported Cu-based oxide catalysts were investigated to reveal the mechanism of the microstructure of Ce O₂ on the denitration activity and the improvement of the anti-O₂/H₂O/SO₂ performance of cerium-supported Cu-based oxide catalysts.The results show that the microstructure of Ce O₂ has a significant effect on the SCR performance of cerium-supported Cu-based oxide catalysts,among which the spherical Cu O_x/Ce O₂-H and tubular Cu O_x/Ce O₂-T catalysts exhibit better denitrification activity,higher N₂ selectivity,and stronger resistance to O₂/H₂O/SO₂.（3）DRIFTs characterization and kinetic analysis were used to reveal the essential reasons for Ce O₂ microstructure to improve the performance of CO-SCR,establish the structure-activity correlation between Ce O₂ microstructure and the physical&chemical properties/SCR performance of cerium-supported Cu-based oxide catalysts,and clarify the microstructure of the dominant cerium-supported Cu-based oxide catalyst.The results showed that the cerium dioxide particles with both（100）and（111）crystal planes were more favorable for the coordination of Cu²⁺,and the species and number of surface active species of the catalysts were more abundant.In addition,Cu O_x/Ce O₂-H(17 k J mol^-1)and Cu O_x/Ce O₂-T(30 k J mol^-1)showed lower apparent activation energies,which further confirmed this conclusion.It is proved that it is feasible to construct high activity and strong resistance O₂/H₂O/SO₂ cerium-supported Cu-based oxide catalysts by regulating the microstructure of cerium dioxide.