Study On Ni-based Bimetallic MOF Synthesis And Low Temperature Selective Catalytic NO Reduction By CO

Industrial waste gas usually contains atmospheric pollutants such as nitrogen oxides（NO_x）and carbon monoxide（CO）.Large amounts of emissions will cause serious environmental pollution and pose a huge threat to human health.Selective catalytic NO reduction by CO（CO-SCR）technology was considered to be a promising technology for the removal of industrial NO_x.At present,the key to the denitration treatment of stationary source waste gas was to solve the problem of de NO_x in a low temperature environment where the flue gas temperature drops below 280°C after the flue gas was desulfurized and electrostatic precipitation dust removal treatment process.Therefore,the development of a low-temperature high-efficiency de NO_x catalyst has important theoretical and practical significance.Studies have shown that Ni-based metal organic framework catalysts exhibited good SCR de NO_x activity,high specific surface area,high dispersibility,and good stability,and had great application potential.In this paper,Ni-MOFs were optimized,a series of bimetallic Fe_x-Ni_1-x-MOFs and Ti_x-Ni_1-x-MOFs catalysts were prepared,and the de NO_xactivity of these catalysts under simulated flue gas was investigated.At the same time,the structure and physical and chemical properties of the catalyst were investigated through systematic modern characterization methods,and the reaction mechanism of the catalyst was discussed in depth.The main research results are as follows:（1）Bimetallic Fe_x-Ni_1-x-MOFs catalyst with rod-like structure was synthesized by solvothermal method.Compared with single metal Fe-MOF and Ni-MOF catalysts,Fe_x-Ni_1-x-MOFs catalyst Fe:Ni=（0.14～0.33）:（0.86～0.67）when NOx conversion rate exceeds 225～450 ^oC temperature window 95%.Among them,Fe_0.33-Ni_0.67-MOF can reach100%NOx conversion rate at 230 ^oC,which is 40%higher than Ni-MOF.In situ FT-IR analysis found that the doped Fe sites serve as NO_xstorage sites and can anchor nitrate and nitrite species.The formation of the Fe-O-Ni composite bond increases the number of defect sites in the catalyst,and at the same time increases the ratio of Ni³⁺on the catalyst surface to the oxygen Oαspecies adsorbed on the surface,thereby promoting the Fe³⁺+Ni²⁺?Fe²⁺+Ni³⁺redox cycle,enhancing Low temperature catalytic activity of the catalyst.（2）The Ti_x-Ni_1-x-MOFs catalyst was synthesized by solvothermal method.This study found that a small amount of Ti doping is beneficial to improve the SCR de NO_x activity of the catalyst,and the Ti_0.2-Ni_0.8-MOF catalyst has the best activity.At 200 ^oC,99%de NO_xefficiency can be achieved,and the Ti_0.2-Ni_0.8-MOF-M catalyst was prepared by microwave within 2 h.In addition,through a series of characterization analyses,we can observe that the microwave method successfully introduced Ti into the Ni-MOF framework,maintained the original crystal structure and slightly improved the catalytic performance of SCR.