Effect of Mo on the selective catalytic reduction of NO_x with NH₃ in the magnetic separation of rare earth tailings

Mo/magnetic separation rare earth tailing catalyst was prepared by hydrothermal method. XRD, SEM–EDS, XPS, H₂-TPR, NH₃-TPD and BET were used to investigate the effect of Mo modification on the performance of rare earth tailing catalyst. Compared with the original tailings, Mo modification significantly improved the denitrification performance of the catalyst. When the modification amount was 7.5% (mass fraction), the denitrification efficiency of the catalyst reached a maximum of 82% at 350 °C, and the selectivity of N₂ remained above 55%. The interaction between Mo and Fe increased the concentration of Mo⁵⁺ and Fe³⁺ on the catalyst surface and promoted the oxidation of NO, Mo modification not only enriched the type and number of acidic sites on the catalyst surface, but also increased the specific surface area and redox capacity of the catalyst, which was conducive to the NH₃-SCR reaction and improved the denitrification performance of the catalyst.