LaBO3钙钛矿催化剂的VOCs催化燃烧特性

采用共沉淀法制备了LaBO3(B=Cr、Fe、Mn、Co、Ni)钙钛矿催化剂,并用XRD、BET、H2-TPR、O2-TPD等手段对其进行了表征,考察了催化剂对苯、甲苯、乙酸乙酯和丙酮的催化燃烧性能.结果表明,Cr、Fe钙钛矿晶相中存在少量的La2CrO6和La2O3杂晶相,破坏了其活性结构.Mn、Co、Ni则能与La形成完善的钙钛矿晶相,且表现出优良的催化性能,其中LaMnO3为阳离子缺陷结构,存在较丰富的晶格氧,更适合催化燃烧C—H键键能较高和难以活化的有机分子(如苯);LaCoO3、LaNiO3属于阴离子缺陷钙钛矿结构,存在更丰富的表面氧,更适合催化燃烧易在低温下活化的含氧类有机分子(如乙酸乙酯、丙酮).

Catalytic properties of LaBO3 perovskite catalysts in VOCs combustion

Perovskite-type catalysts of LaBO3 (B = Cr, Mn, Fe, Co, Ni) were prepared by copercipitation method and characterized by XRD, BET, H2-TPR and O2-TPD techniques. The catalytic performance of catalysts was evaluated for combustion of benzene, toluene, ethyl acetate, and acetone. Except for perovskite structure, La2CrO6 and La2O3 also would be formed in LaCrO3 and LaFeO3 catalysts, which led to destruction of active structure. But LaMnO3, LaCoO3 and LaNiO3 catalysts showed the perfect perovskite structure that resulted in high catalytic activity. Among these catalysts, LaMnO3 has richer lattice oxygen, and more favorably be used in catalytic combustion of VOCs with high C-H bond (such as benzene). In contrast, LaCoO3 and LaNiO3 presented richer surface oxygen because of its structures of anion defects, and were good catalysts for catalytic combustion of oxygenated VOCs (such as ethyl acetate and acetone).