助催化剂对Fe1-xO基氨合成催化剂还原性能的影响

当助催化剂存在是地，Ｆｅ１－ｘＯ基催化剂的还原性能明显优于Ｆｅ３Ｏ４基催化剂，其原因是铝、钾、钙的氧化物对催化剂母体相Ｆｅ１－ｘＯ和Ｆｅ３Ｏ４还原性能的影响不同。由于Ａｌ＾３＋大量地进入Ｆｅ３Ｏ４的晶格而强烈地阻止Ｆｅ３Ｏ４的还原，只有少量的Ａｌ＾３＋能进入Ｆｅ１－ｘＯ晶格，因此对Ｆｅ１－ｘＯ的还原影响很小；

THE EFFECT OF PROMOTERS ON REDUCTION PERFORMANCE OF Fe 1- x O BASED AMMONIA SYNTHESIS CATALYST

The reduction performance of fused iron catalyst for ammonia synthesis is closely related with the phase composition of its precursor. However, the main reason why reduction performance of Fe 1- x O based catalyst is superior to that of Fe 3O 4 based catalyst is the different effects of aluminum, potassium and calcium oxides on the reduction of Fe 1- x O and Fe 3O 4. Al 2O 3 strongly affects the reduction of Fe 3O 4 based catalyst owing to Al 3+ inserting into the crystal structure of Fe 3O 4, but it affects the reduction of Fe 1- x O based catalyst weakly because only a small amount of Al 3+ can insert into the crystal structure of Fe 1- x O. A large amount of Ca 2+ inserted into the crystal structure of Fe 1- x O does not hinder the reduction of Fe 1- x O based catalyst. When K 2O is added into the precursor of the catalysts, it accelerates the reduction of Fe 1- x O based catalyst, but not the reduction of Fe 3O 4 based catalyst.