Effect of Bimetal Element Doping on the Low-Temperature Activity of Manganese-Based Catalysts for NH₃-SCR

A series of novel Mn₆Zr_1-xCo_x denitrification catalysts were prepared by the co-precipitation method. The effect of co-modification of MnO_x catalyst by zirconium and cobalt on the performance of NH₃-SCR was studied by doping transition metal cobalt into the Mn₆Zr₁ catalyst. The ternary oxide catalyst Mn₆Zr_0.3Co_0.7 can reach about 90% of NO_x conversion in a reaction temperature range of 100-275°C, and the best NO_x conversion can reach up to 99%. In addition, the sulfur resistance and water resistance of the Mn₆Zr_0.3Co_0.7 catalyst were also tested. When the concentration of SO₂ is 200ppm, the NO_x conversion of catalyst Mn₆Zr_0.3Co_0.7 is still above 90%. 5 Vol% H₂O has little effect on catalyst NO_x conversion. The results showed that the Mn₆Zr_0.3Co_0.7 catalyst has excellent resistance to sulfur and water. Meanwhile, the catalyst was systematically characterized. The results showed that the addition of zirconium and cobalt changes the surface morphology of the catalyst. The specific surface area, pore size, and volume of the catalyst were increased, and the reduction temperature of the catalyst was decreased. In conclusion, the doping of zirconium and cobalt successfully improves the NH₃-SCR activity of the catalyst.