Ge-Mn共掺杂对V-Mo-O/TiO2催化剂低温脱硝活性的影响

采用共沉淀法制备Ge-Mn共改性TiO₂载体，考察了V-Mo-O/Ge-xMn-TiO₂催化剂的低温氨选择性催化还原 (NH₃-SCR) 活性和抗硫稳定性。Ge-Mn的加入可显著提高催化剂在低温窗口下的脱硝活性，且具有较高的N₂选择性和抗硫稳定性。当Ge:Mn:Ti的原子摩尔比为0.004:0.04:1，在140 ℃时脱硝活性为92%。催化剂的N₂吸附-脱附、NH₃-TPD、H₂-TPR、XRD和XPS分析结果表明：Mn加入使催化剂的介孔增加，表面总酸性位和中高强度酸性位量显著增加，从而增加了催化剂对NH₃的吸附活化和对SO₂吸附的抑制；Mn与V、Mo、Ge活性组分发生了强电子相互作用，使V⁵⁺含量增加，且使低温活性组分的氧化还原循环易于进行，进而增加了催化剂的低温脱硝活性。这说明增加的表面总酸性位和中高强度酸性位量、增加的V⁵⁺和由此形成的低温条件促进了活性组分氧化还原循环，最终提高了催化剂的低温活性和高抗硫稳定性。本研究可为低温脱硝催化剂的研发及应用提供参考。

Effect of Ge-Mn co-doping on low-temperature denitrification activity of V-Mo-O/TiO2 catalyst

Ge-Mn co-modified TiO2 support was prepared by co-precipitation method, and the activity and sulfur resistance of low-temperature ammonia selective catalytic reduction (NH3-SCR) and sulfur resistance of V-Mo-O/Ge-xMn-TiO2 catalysts were investigated. Compared with traditional V-Mo-O/TiO2 catalysts, the addition of Ge-Mn significantly improved the denitrification activity of the catalyst at low temperature window, and at the same time had high N2 selectivity and stable sulfur resistance. When the Ge:Mn:Ti atomic molar ratio was 0.004:0.04:1, the denitrification activity could reach 92% at 140 °C. The N2 adsorption-desorption, NH3-TPD, H2-TPR, XRD and XPS analysis results of the catalyst showed that the addition of Mn increased the mesoporosity of the catalyst, meanwhile the total surface acid sites and the amount of medium and high strength acid sites increased significantly, which increased the catalyst's adsorption activation of NH3 and inhibition of SO2 adsorption. Mn interacted with the active components of V, Mo, and Ge, which increased the content of V5+ and facilitated the redox cycle of the active components at low temperature, thus the low-temperature denitration activity of the catalyst was increased. Therefore, the increase of total surface acid sites, medium-strength acid sites, high-strength acid sites, and V5+ content and the formation of a low-temperature facile redox cycle of active components improved the catalyst's low-temperature activity and high sulfur resistance stability.