摘要
系统考察了稀土氧化物La2 O3 ,Nd2 O3 ,Sm2 O3 ,Dy2 O3 ,Sc2 O3 和CeO2 作为助催化剂对Fe1-xO基催化剂性能的影响 .结果表明 ,稀土氧化物与Fe1-xO作用生成了一种作为隔离体的复合氧化物REFeO3 ,从而促进了催化剂的还原 ,这种促进作用随稀土离子半径不同呈规律性变化 .添加不同稀土氧化物的Fe1-xO催化剂的还原都存在补偿效应 ,各系列催化剂还原反应的转效温度与所添加稀土元素的离子半径呈正比关系 (CeO2 除外 ) .稀土氧化物可以有效地提高催化剂的低温活性 ,其添加量的变化对催化剂活性的促进作用规律与对催化剂还原性能的促进作用规律一致 .
The regulation effect of rare earth oxides La 2O 3, Nd 2O 3, Sm 2O 3, Dy 2O 3, Sc 2O 3 and CeO 2 on the performance of Fe 1-x O catalysts for ammonia synthesis has been investigated systematically by TG, activity test and XRD. The reduction performance is promoted by the addition of rare earth oxides. This is due to the formation of a compound REFeO 3 between rare earth oxide and Fe 1- x O that acts as a separant in the catalyst. The promotion degree of rare earth oxide for the reduction of Fe 1-x O is strengthened with increase of the radius of rare earth metal ion. For each series of the catalysts with different rare earth oxides, the Arrhenius compensation effect exists in their reduction kinetics. The transformation temperature of reduction varies with the radius of metal ion added (except for CeO 2). The activity at low temperature is raised effectively by the addition of various rare earth oxides. Thus, the regulation effect of rare earth oxide on the activity is the same as that on the reduction.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第3期199-203,共5页
基金
国家自然科学基金!(批准号 2 970 60 11)
浙江省青年科技人才培养专项资金!(RC9702)
关键词
氧化铁
氨合成催化剂
稀土氧化物
助催化剂
iron oxide, ammonia synthesis catalyst, rare earth oxide, co catalyst
