锑掺杂对钒钛系催化剂低温脱硝活性的影响

用浸渍法制备Sb-V₂O₅-TiO₂催化剂，在质量分数3%V₂O₅-TiO₂催化剂基础上，研究锑的负载量、焙烧温度对催化剂活性的影响。结果表明，锑的负载量为11%（质量分数），500 ℃焙烧的催化剂具有最佳的SCR活性，在进口浓度为0.07% NO_x、O₂体积分数5%、空速27 000 h^-1的条件下，170 ℃时脱硝活性可达92%。对催化剂进行H₂-TPR表征，发现锑修饰后的催化剂氧化能力增强，使催化剂效率上升。通过XPS和NH₃-TPD表征测试，催化剂表面的锑主要以五价的形式存在且随着锑负载量的增加催化剂表面酸性增强。考察SO₂和H₂O对催化剂的影响发现，加锑催化剂具有一定的抗硫抗水性能。通过FT-IR、TG、孔隙结构测试表明，锑的加入可以有效地抑制硫酸铵盐在催化剂表面的聚集，从而延长催化剂的寿命。

Effect of antimony doped vanadium-titanium catalyst on low-temperature NH3-SCR activity

Sb-V₂O₅-TiO₂ catalysts were prepared by wet impregnation method. The effect of antimony loadings and calcination temperatures on the activity of catalysts were investigated on the basis of 3%V₂O₅-TiO₂. The results indicate that the catalyst with 11% Sb loading, calcined at 500℃, has the best activity of SCR. The NO_x conversion could reach 92% at 170℃ with the inlet NO_x concentration of 0.07%, the O₂ volume fraction of 5%, and the space velocity of 27 000 h^-1. The H₂-TPR data reveal that the increase of activity can be attributed to the promotion of the catalyst oxidation ability by the modifying of antimony. Sb is mainly in the pentavalent antimony form on the surface of the catalyst, and the increase in surface acidity of the catalyst is identified by means of XPS and NH₃-TPD. The effects of SO₂ and H₂O on the catalyst is also studied, showing that the Sb-V₂O₅-TiO₂ has an excellent catalytic activity in the presence of H₂O and SO₂. FT-IR, TG and pore structure test results suggest that the addition of Sb can effectively inhibit the aggregation of ammonium sulfate on the catalyst surface, thereby improving the service life of the catalyst.