氧化铝载体硫酸化对锰铈催化剂SCR脱硝性能的影响

Effect of sulfuric acid modification of Al2O3 support on the SCR performance of MnCe/Al2O3 catalysts

分别以硫酸改性前后的氧化铝为载体,采用浸渍法制备了锰铈催化剂,对其NH3-SCR脱硝性能进行评价,并采用XRD、BET、NH3-TPD、H2-TPR以及FT-IR对催化剂进行了表征。结果表明,改性降低了金属的分散性和氧化性,增加了酸量,特别是B酸量;催化剂的最佳脱硝温度窗口向高温扩展,活性温度窗口范围变宽,并且,改性液浓度越大变化幅度越大。当反应温度在200-250℃时,未改性催化剂与采用0.2mol/L硫酸改性的催化剂具有接近的催化活性,但改性后的催化剂具有更高的抗水抗硫活性,250℃时脱硝率可达70%。

With unmodified and modified Al 2O 3 as the support, a series of Mn-Ce catalysts were prepared by impregnation method and characterized by XRD, BET, NH 3-TPD, H 2-TPR and FT-IR. The catalytic performance in the NH 3-SCR of NO x was investigated. The results show that the sulfuric acid modification to the support decreased the metal dispersion and weakened the oxidization property of the catalyst, increased the concentration of acid sites, especially, B acid sites. Besides, the optimum temperature window ranges for SCR of the modified catalyst moved to higher temperature and broadened, and increased with the increase of modified liquid concentration. The unmodified catalyst and the catalyst modified by 0.2 mol/L solution had same SCR reactivity within the temperature range of 200-250 ℃. However, the modified catalyst showed the best resistance to SO 2 and H 2O and presented 70% NO conversion at 250 ℃.