摘要
Sulfur dioxide(SO_(2))frequently coexist with volatile organic compounds(VOCs)in exhaust gas.The competitive adsorption of SO_(2) and VOCs can adversely affect the efficiency of catalytic combustion,leading to catalyst poisoning and irreversible loss of activity.To investigate the impact of sulfur poisoning on the catalysts,we prepared the MnO_(2)/Beta zeolite,and a corresponding series of sulfur-poisoned catalysts through in-situ thermal decomposition of(NH_(4))_(2)SO_(4).The decrease in toluene catalytic activity of poisoned MnO_(2)/Beta zeolite primarily results from the conversion of the active species MnO_(2) to MnSO_(4).However,the crystal structure and the porous structure of MnO_(2)/Beta zeolite were stable,and original structure was still maintained when 1.6%(mass)sulfur species were introduced.Furthermore,the extra-framework Al of Beta zeolite could capture sulfur species to generate Al2(SO_(4))_(3),thereby reducing sulfur species from reacting with Mn^(4+) active sites.The combination of sulfur and Beta zeolite was found to directly produce new strong-acid sites,thus effectively compensating for the effect of reduced Mn4+active species on the catalytic activity.
基金
supported by the National Natural Science Foundation of China(21577094)
the Zhejiang Public Welfare Technology Research Project(LGG19B070003).
