Mn-Fe-Ce/Al2O3/堇青石催化剂低温 NH3-SCR 脱硝性能研究

摘要

Mn-Fe-Ce/Al2O3/cordierite monolithic catalyst was prepared via coating Al sol on honeycomb-like cordierite carrier by sol-gel method, loading Mn and additives by impregnation method. The Mn-Fe-Ce/Al2O3/cordierite monolithic catalyst was used for low-temperature selective catalytic reduction (SCR) of NOx with ammonia. The results show that the activity of the catalyst can be significantly improved after doping Fe and Ce. The conversion of NO can be improved by doping Ce and Fe from 86.3% to 93.5% at 120 ℃ with a gas hourly space velocity(GHSV) of 4 000 h-1. The conversion of NO can be more than 93% at 120~ 300 ℃. The XRD,BET, NH3 adsorption and H2-TPR show that the catalyst after adding proper Ce has larger specific surface area and pore volume, contains more acidic site, which can promote NH3 adsorption and NO oxidation activity. These factors may lead to the increasing of the SCR activity of Mn-Fe-Ce/Al2O3/CC catalyst.%先采用溶胶凝胶法在堇青石蜂窝陶瓷载体上涂覆铝溶胶浆液，再通过浸渍法负载活性组分 Mn 和助剂，制备了 NH3选择性催化还原 NOx 低温脱硝催化剂 Mn-Fe-Ce/Al2O3/堇青石，实验结果显示：Ce 和 Fe 的添加可以明显提高催化剂的低温脱硝活性，在体积空速4000 h-1时和120℃条件下，NO 转化率由86.3%提高到93.5%，并且在120～300℃范围内，NO 的转化率均保持在93%以上。XRD、BET、NH3-TPD 和 H2-TPR 结果表明：Fe 和 Ce 改性后增加了催化剂的比表面积和孔体积、酸性位点、NH3的吸附能力和氧化能力，提高了催化剂的 SCR 活性。