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化学学报
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化学学报 ›› 1994, Vol. 52 ›› Issue (11): 1076-1081. 上一篇    下一篇

研究论文

钙钛石型复合氧化物催化剂LaMn~yCo~1~-~yO~3催化性能的研究 Ⅱ. 过渡金属离子之间的相互作用与在氨氧化反应中的催化性能

刘社田;于作龙;吴越   

  1. 中国科学院长春应用化学研究所
  • 发布日期:1994-11-15

A study of the catalytic properties of perovskite-type oxides LaMn~y Co~1~-~yO~3 Ⅱ.The interaction between transition metal ions and their catalytic property in ammonia oxidation

LIU SHETIAN;YU ZUOLONG;WU YUE   

  • Published:1994-11-15

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发现钙钛石型复合氧化物LaMn~yCo~1~-~yO~3中B位过渡金属离子Mn,Co 之间的相互作用及其氧化还原性是影响氨氧化反应中NO选择的重要因素.B位少量掺杂可促进过渡金属离子的氧化还原性,但B位组成相当时(y=0.5),则不利于它们的氧化还原.富锰区(y>0.5),Mn^3^+-O^2^--Mn^4^+的超交换作用对样品的磁性及NO 选择性起决定作用,富钴区(y<0.5),Co^2^+Co^Ⅲ离子的存在及其浓度是影响NO选择性的主要因素.y=0.5时样品的结构决定了样品的强铁磁性质,并由于Mn^3^+-O^2^--Co^3^+之间不易氧化还原因而对生成NO不利

关键词: 氧化还原反应, 氧化锰, 氧化钴, 氧化镧, 钙钛矿型结构, 氨氧化, 电磁性质, 催化性能

The interaction between the two transition metal Mn, Co ions on B-site and their redox property are the important factors influencing the NO-selectivity in ammonia oxidation The NO-selectivity is related to the redox ability of Mn3+ ?Mn4+ or Co2+ ?Co3+, which could be promoted by doping a small amount of foreign transition metal ions on B-site of matrix samples, but not for the sample with the composition of y = 0.5. In Mn-rich region (y > 0.5), the magnetic property and NO-selectivity are controlled by the ferromagnetic superexchange of Mn3+-O2-Mn4+. The main factor influencing the NO-selectivity of Co-rich samples (y < 0.5) is the concentration of Co2+ and CoIII ions. The strong ferromagnetism of the sample with the composition of y = 0.5 may be due to its crystal structure, and the redox between Mn3+ and Co3+ is unfavorable for the producing of NO. There exists a close relationship between the NO-selectivity and the valence, d-electron configuration, electron transmission rate and the interaction between the electrons.

Key words: OXIDATION REDUCTION REACTION, MANGANESE OXIDE, COBALT OXIDE, LANTHANUM OXIDE, PEROVSKITE TYPE STRUCTURE, AMMONOXIDATION, ELECTROMAGNETIC PROPERTIES, CATALYTIC BEHAVIOUR

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