Abstract:

In order to enhance the performance of low-temperature denitration catalyst, a series of nitrogen doped vanadium titanium honeycomb catalysts were prepared by extrusion molding. The effect of nitrogen doping amount on the low-temperature activity and stability of the catalyst were discussed. The catalysts were characterized by XRD, BET, SEM, XPS, H₂-TPR, NH₃-TPD and O₂-TPD. The results showed that nitrogen doping significantly enhanced the low temperature denitration performance of the catalysts, which worked well in the temperature range of 140—200℃. Among them, the catalyst with the molar ratio of nitrogen to titanium of 0.2 had the best deNO _x efficiency. During the 72-hours stability test at 200℃, the NO conversion rate was basically kept at 86.6%. Nitrogen doping could reduce vanadium titanium catalyst particle size, increase the specific surface area and pore volume, as well as the ratio of surface V⁴⁺and chemically adsorbed oxygen O_α. With the increase of the acidic sites on the surface, the adsorption capacity of NH₃ on the catalyst surface was increased, leading to the enhanced redox capacity and the improved low temperature denitration performance of the catalyst.

Key words: N-doping, vanadium-titanium catalyst, honeycomb catalyst, low temperature denitration

摘要：

为了提升催化剂的低温脱硝性能，利用挤出成型法制备了一系列氮掺杂钒钛蜂窝式催化剂，考察了氮掺杂量对催化剂低温脱硝性能的影响及其稳定性，并通过XRD、BET、SEM、XPS、H₂-TPR、NH₃-TPD和O₂-TPD等分析方法表征催化剂。结果表明：氮掺杂钒钛催化剂的低温脱硝性能显著提高，在140~200℃温度区间催化剂的脱硝性能良好，其中以氮钛摩尔比为0.2的催化剂具有最优的脱硝效果，并在200℃连续72h的稳定性测试过程中，表现出了良好的脱硝稳定性。氮掺杂能够使钒钛催化剂颗粒粒径变小，比表面积和孔容增大，表面V⁴⁺和化学吸附氧O_α的比率增加，表面酸性位点数量增加，使催化剂表面NH₃吸附能力增强，氧化还原能力提高，促进了催化剂低温脱硝性能的提升。

关键词: 氮掺杂, 钒钛催化剂, 蜂窝式催化剂, 低温脱硝