Co3O4/CeO2 CO氧化的原位红外光谱研究

采用沉淀氧化法制备了Co₃O₄/CeO₂催化剂。分别在干、湿条件下进行了一氧化碳氧化反应研究。运用FT-IR表征手段,在钴铈复合氧化物上进行了CO吸附及CO/O₂共吸附研究。结果表明,与纯的Co₃O₄样品相比,Co₃O₄/CeO₂具有明显的抗湿气能力。Co₃O₄/CeO₂催化剂在进行CO氧化时,表面形成了类碳酸盐物种。当环境温度低于453 K时,催化剂上类碳酸盐的生成与形成类碳酸盐物种后受热分解存在着动态平衡。当环境温度高于493 K,催化剂上生成的类碳酸盐物全部受热分解。氧化铈的加入提高了催化剂的抗湿气性能。较小粒径的Co₃O₄与CeO₂产生的强相互作用可使CeO₂向Co₃O₄提供氧,因而间接提供了CO氧化需要的氧。

In situ FT-IR study on CO oxidation over Co3O4/CeO2 catalyst

Co3O4/CeO2 catalyst was prepared by co-precipitation-oxidation method.Adsorption of carbon monoxide and the co-adsorption of CO/O2 over Co3O4/CeO2 sample were investigated.In situ FT-IR analysis of the mechanism in CO oxidation was interpreted over Co3O4/CeO2 sample.Effects of the reaction conditions on the catalytic performance over Co3O4/CeO2 catalyst for carbon monoxide oxidation was investigated at humid and dry conditions.Results indicated that the addition of cerium to the cobalt oxide was beneficial for CO oxidation over Co3O4 at humid condition.The formation of carbonate species with reaction on Co3O4/CeO2 composite oxide slightly deactivated the catalyst.When the temperature was as low as 453 K,the dynamic equilibrium of formation and decomposition of carbonate species existed in Co3O4/CeO2 composite oxide catalyst.The carbonate species disappeared above 493 K.The strong interaction between CeO2 and Co3O4 may contribute to the excellent water resistance for low-temperature CO oxidation over Co3O4/CeO2 catalyst at humid condition.