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<p>As a natural mineral, Bayan Obo rare earth tailings are an environmentally friendly and cost-effective. They contain Fe, Ce, Nb and other active elements that facilitate catalytic denitrification, with Fe and Ce exhibiting pronounced synergistic effects due to their complex co-occurrence relationships. In this study, we developed a catalyst by using Bayan Obo rare earth tailings as a carrier and incorporating small amounts of Co and Mn as active components. The influence of these additives was systematically investigated, focusing on&#xa0;denitrification performance, pore structure, surface acidity redox properties and elemental valence states. The catalysts were characterized through XRD, SEM, BET, NH<sub>3</sub>-TPD and H<sub>2</sub>-TPR. Results demonstrated that the Co–Mn (3%,4%)-modified rare earth tailings achieved 95% denitrification efficiency within a low-temperature range of 150–300&#xa0;°C. Co–Mn co-doping increased the specific surface area, with the 5%Mn-2.5%Co-modified catalyst exhibiting optimal structural parameters (75.3188 m<sup>2</sup>/g surface area and 10.2179&#xa0;nm pore diameter). Furthermore, the addition of Co and Mn enhanced surface acidity, as evidenced by a pronounced weak acid desorption peak in NH<sub>3</sub>-TPD, which promoted low-temperature activity. Redox capacity analysis revealed that Mn doping concentration positively correlated with catalytic redox potential. Co incorporation further amplified this effect by stabilizing low-valent MnO<sub>x</sub> species (e.g., Mn<sup>3</sup>⁺), thereby suppressing MnO<sub>2</sub> over-oxidation and minimizing undesirable NH<sub>3</sub> oxidation via Mn<sub>2</sub>O<sub>3</sub> inhibition.</p>

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Effect of Co–Mn combined modification of rare earth tailing catalyst on denitrification performance of NH3-SCR

  • 期刊论文

  • 发表日期：

    2025年4月2日

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  • Ye Yuqiao,
  • Wang Xinzhan,
  • Hou Limin

摘要

As a natural mineral, Bayan Obo rare earth tailings are an environmentally friendly and cost-effective. They contain Fe, Ce, Nb and other active elements that facilitate catalytic denitrification, with Fe and Ce exhibiting pronounced synergistic effects due to their complex co-occurrence relationships. In this study, we developed a catalyst by using Bayan Obo rare earth tailings as a carrier and incorporating small amounts of Co and Mn as active components. The influence of these additives was systematically investigated, focusing on denitrification performance, pore structure, surface acidity redox properties and elemental valence states. The catalysts were characterized through XRD, SEM, BET, NH3-TPD and H2-TPR. Results demonstrated that the Co–Mn (3%,4%)-modified rare earth tailings achieved 95% denitrification efficiency within a low-temperature range of 150–300 °C. Co–Mn co-doping increased the specific surface area, with the 5%Mn-2.5%Co-modified catalyst exhibiting optimal structural parameters (75.3188 m2/g surface area and 10.2179 nm pore diameter). Furthermore, the addition of Co and Mn enhanced surface acidity, as evidenced by a pronounced weak acid desorption peak in NH3-TPD, which promoted low-temperature activity. Redox capacity analysis revealed that Mn doping concentration positively correlated with catalytic redox potential. Co incorporation further amplified this effect by stabilizing low-valent MnOx species (e.g., Mn3⁺), thereby suppressing MnO2 over-oxidation and minimizing undesirable NH3 oxidation via Mn2O3 inhibition.