Effects of SO2 on standard and fast SCR over CeWOx: A quantitative study of the reaction pathway and active sites
Effects of SO2 on standard and fast SCR over CeWOx: A quantitative study of the reaction pathway and active sites
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SO2 对 CeWOx 上标准和快速 SCR 的影响：反应途径和活性位点的定量研究
DOI：
10.1016/j.apcatb.2021.120784
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发表时间：
2021-10-14
影响因子：
22.1
通讯作者：
He, Hong
中科院分区：
文献类型：
--
作者：
Huo, Yanlong;Liu, Kuo;He, Hong
采用瞬态反应实验和原位DRIFTS研究了SO2对CeWOx上NO2、NH3和NO吸附量的影响以及快速SCR和标准SCR的反应途径。在快速SCR过程中，SO2的负面影响不太严重。SO2吸附抑制NO吸附和“亚硝酸盐路径”，这对于低温下的标准SCR是不利的。对于快速SCR，虽然“亚硝酸盐途径”和“NH4NO3途径”受到抑制，但由于NO2吸附产生的硝酸盐较多，NH4HSO4分解速度加快，促进了NO气体、表面硝酸盐和吸附的NH3之间的反应，使得SO2的抑制作用减弱。B酸中心的活性更高，对SO2的SCR反应起主要作用。NH_4HSO_4可能不是失活的主要原因。当H_2O和SO_2存在时，“亚硝酸盐途径”受到严重抑制，“NH_4NO_3途径”缺失，导致活性下降。
The influence of SO2 on the amounts of NO2, NH3 and NO adsorbed on CeWOx and the reaction pathway of fast and standard SCR were investigated using transient reaction experiments and in situ DRIFTS. The negative effect of SO2 was less severe during fast SCR. The SO2 adsorption inhibited NO adsorption and the "nitrite path", which is detrimental for standard SCR at low temperatures. For fast SCR, although "nitrite path" and "NH4NO3 path" were inhibited, the greater amount of nitrates from NO2 adsorption, acceleration of NH4HSO4 decomposition, and promoted reaction between the NO gas, surface nitrates and adsorbed NH3 made the inhibitory effect of SO2 less severe. Bronsted acid sites are more active and make the main contribution to SCR with SO2. NH4HSO4 may not be the main cause of deactivation. When H2O and SO2 were present, "nitrite path" was seriously inhibited and "NH4NO3 path" was absent, causing decreased activity.