低温等离子改性对Ce/TiO2-Al2O3脱硝性能的影响

采用等体积浸渍法制备了的Ce/TiO2-Al2O3(不同摩尔比例)脱硝催化剂.通过性能比较,将最佳Ti/Al比例(2:1)的Ce/TiO2-Al2O3催化剂用于低温等离子体改性.改性后催化剂的整体性能包括:NO转化率、N2选择性、稳定性都有了一定的提高,改性前后催化剂在350℃左右的最佳脱硝效率分别为:90.23％,95.67％.此外,由催化剂抗碱金属实验结果可知,改性后的催化剂有更好的抗性,改性前后脱硝效率分别为63.25％,70.54％.并且由XRD,BET,FTIR,UV-vis,NH3-TPD,SEM,XPS,H2-TPR一系列表征结果可知,催化剂整体性能的提高与等离子体改性有关,而且低温等离子体改性作用主要体现在两方面:第一、增加了催化剂表面的Ce3+物种,促进了化学吸附氧的生成;第二、催化剂先经等离子体改性再煅烧,有利于增加催化剂表面的Bronsted酸与Lewis酸位点.

Effect of Non-thermal Plasma Treated Ce/TiO2-Al2O3 Catalyst on Its NH3-SCR Activity

The Ce/TiO2-Al2O3 catalysts with different molar ratios of supports were prepared by the incipient-wetness impregnation method , followed by the performance evaluation , to sort out the best ratio of modified sample ( Ti/Al=2:1 ) .After the treatment of non-thermal plasma , the whole performances of the catalyst including NO conversion , N2 selectivity and stability were well improved , at about 350 ℃, the optimal NO conversion efficiency is respectively 90.23％, 95.67％before or after the modification . Besides , according to the results of alkali metal resistance experiment , the modified catalyst has a better resistance and the NO conversion efficiency of treated and untreated samples is respectively 63.25％, 70. 54％.Based on the analytical consequence of XRD , BET, FTIR, UV-vis, NH3-TPD, SEM, XPS, H2-TPR, all perfect activity of the Ce/TiO2-Al2O3 catalyst is greatly related with the non-thermal plasma treatment , which is for two cases that it can increase the amount of Ce 3+ species to generate more chemisorbed oxygen , the way of modification and then calcination is beneficial for the increment of Bronsted and Lewis acidic sites .