Scholarlink

<p>Mn-modified catalysts were prepared by impregnation using magnetically separated rare earth tailings concentrate (MSRETC) as the mineral precursor. Nominal Mn loading was defined on an elemental-Mn basis relative to the mass of MSRETC. Mn modification shifted the NH<sub>3</sub>-SCR activity window toward lower temperatures, and the 3 wt% Mn/MSRETC sample reached a maximum NO<sub><i>x</i></sub> conversion of 87.4% at 200&#xa0;°C. The BET surface area and pore volume increased from 23.12 m<sup>2</sup> g<sup>−1</sup> and 0.1087 cm<sup>3</sup> g<sup>−1</sup> for MSRETC to 62.31 m<sup>2</sup> g<sup>−1</sup> and 0.1684 cm<sup>3</sup> g<sup>−1</sup> for the 3 wt% sample. Surface Mn species were confirmed by Mn 2p XPS, whereas XRD did not resolve unambiguous crystalline MnO<sub><i>x</i></sub> peaks at these low loadings. NH<sub>3</sub>-TPD indicated changes in the amount and strength distribution of acid sites, and H<sub>2</sub>-TPR showed that the low-temperature reduction-peak maximum shifted from approximately 502&#xa0;°C for 1 wt% Mn/MSRETC to 457&#xa0;°C for 3 wt% Mn/MSRETC. Transient DRIFTS trends are consistent with contributions from both adsorbed-NH<sub><i>x</i></sub>/gaseous-NO<sub><i>x</i></sub> and adsorbed-NO<sub><i>x</i></sub>/gaseous-NH<sub>3</sub> pathways; however, the available spectra do not support definitive assignments of individual bands or a dominant mechanism. These results demonstrate a feasible route for valorizing rare earth tailings as low-temperature SCR catalyst precursors.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Selective catalytic reduction denitrification performance and mechanism of Mn-modified magnetic-separated rare earth tailings catalysts

  • 期刊论文

  • 发表日期：

    2026年7月29日

查看全文
  • Junmao Qie,
  • Jian Chang,
  • Jiaqi Zong,
  • Mengfei Cao,
  • Jiarong Wei,
  • Shuqi Zhang

摘要

Mn-modified catalysts were prepared by impregnation using magnetically separated rare earth tailings concentrate (MSRETC) as the mineral precursor. Nominal Mn loading was defined on an elemental-Mn basis relative to the mass of MSRETC. Mn modification shifted the NH3-SCR activity window toward lower temperatures, and the 3 wt% Mn/MSRETC sample reached a maximum NOx conversion of 87.4% at 200 °C. The BET surface area and pore volume increased from 23.12 m2 g−1 and 0.1087 cm3 g−1 for MSRETC to 62.31 m2 g−1 and 0.1684 cm3 g−1 for the 3 wt% sample. Surface Mn species were confirmed by Mn 2p XPS, whereas XRD did not resolve unambiguous crystalline MnOx peaks at these low loadings. NH3-TPD indicated changes in the amount and strength distribution of acid sites, and H2-TPR showed that the low-temperature reduction-peak maximum shifted from approximately 502 °C for 1 wt% Mn/MSRETC to 457 °C for 3 wt% Mn/MSRETC. Transient DRIFTS trends are consistent with contributions from both adsorbed-NHx/gaseous-NOx and adsorbed-NOx/gaseous-NH3 pathways; however, the available spectra do not support definitive assignments of individual bands or a dominant mechanism. These results demonstrate a feasible route for valorizing rare earth tailings as low-temperature SCR catalyst precursors.