Study on the selective catalytic reduction of NO by Mo/Ce combined-modified NH3 catalyst for magnetic separation of rare earth tailings

Abstract

Natural minerals as catalysts have the advantages of wide source and environmental friendliness. However, it is still challenging to develop mineral-based NH₃-SCR catalysts with high NO conversion and N₂ selectivity at low temperatures. Therefore, we use magnetic separation rare earth tailings with certain catalytic activity and acidic sites as the carrier, and introduce metal elements Mo and Ce with different valence states as active components to stimulate the catalytic activity of magnetic separation rare earth tailings by multi-element co-doping. The catalysts were tested and analyzed by XRD, XPS, BET, NH₃-TPD and other characterization methods. The results show that there is an electronic interaction between Fe, Mo and Ce on the surface of Mo-Ce/magnetic rare earth tailings catalyst. The increase of Fe³⁺, Mo⁵⁺ and Ce³⁺ promotes the adsorption of NH₃ and NO on the surface of the catalyst. With the introduction of Ce, the redox capacity and Brønsted acid strength of the catalyst at low temperature are significantly enhanced, thus accelerating the SCR reaction. The results of this study not only provide a theoretical basis for the high-value utilization of magnetic separation rare earth tailings, but also expand the raw material range of NH₃-SCR denitration catalyst.