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运用 AES,XPS,XRD和 TEM等手段研究了 La Co O3模型催化剂 SO2 中毒过程表面化学状态、晶相结构及表面形貌的变化状况 ,初步推断了 La Co O3钙钛矿型复合金属氧化物催化剂的 SO2 中毒机理 .在 SO2强化中毒过程中 ,SO2 与催化剂的活性组分 La Co O3反应生成硫酸镧和氧化亚钴 ,而在催化剂膜层内部则生成硫酸镧、亚硫酸镧及氧化亚钴 . SO2 对活性组分层的侵入及硫与 La Co O3活性组分的反应破坏了催化剂的钙钛矿结构 ,使得催化剂彻底中毒 .当中毒温度较低及中毒时间较短时 ,硫在膜层中呈峰形分布 ,其浓度随中毒温度及时间的增加而增加 .随中毒温度的升高及中毒时间的增长 ,由于亚硫酸盐的分解作用 ,S在活性层中的浓度反而降低 ,中毒深度则继续增加 .
The changes of surface chemical state, crystal phase structure and surface morphology of LaCo O3 catalyst were studied by means of AES, XPS, XRD and TEM. The results show that La Co O3 perovskite composite metal oxide catalyst SO2 poisoning mechanism.In the process of SO2 poisoning, SO2 reacts with La Co O3, which is the active component of the catalyst, to form lanthanum sulfate and cobaltous oxide, while lanthanum sulfate, lanthanum sulfite and cobaltous oxide are formed inside the catalyst film. Intrusion of SO2 into the active component layer and the reaction of sulfur and La Co O3 active component destroy the perovskite structure of the catalyst and make the catalyst thoroughly poisoned. When the poisoning temperature is low and the poisoning time is short, sulfur is in the film layer With the peak shape distribution, the concentration increased with the increase of temperature and time.With the increase of poisoning temperature and poisoning time, due to the decomposition of sulfite, the concentration of S in the active layer but decreased, the depth of poisoning Continue growing .