预处理Fe基催化剂CO加氢合成低碳烯烃选择性影响研究

Effect of pretreatment of iron catalyst on light olefin selectivity in CO hydrogenation

研究了Fe2O3在CO和H2气氛下预处理对催化剂物相、表面组成和性质的影响及CO加氢合成低碳烯烃反应行为。结果表明,300℃H2预处理后催化剂主要物相结构为Fe3O4和α-Fe,250℃CO预处理后主要物相为Fe3O4,随着CO预处理温度的升高,有碳化铁生成。表面碳化物含量随着CO预处理温度的升高而增加。CO较H2预处理表面碱性增强,CO2和CO吸附显著增加,随着预处理时间的延长,表面积炭降低了CO2和CO吸附。经CO预处理的催化剂具有较高的烯烃选择性,H2预处理的催化剂烯烃选择性相对较低。

Effects of CO and H2 pretreatment on the Fe2O3 catalyst and its catalytic performance on the light olefin production through CO hydrogenation were investigated.It was indicated that the catalyst sample pretreated with H2 at 300 ℃ favored the formation of Fe3O4 and α-Fe phases.Fe3O4 was formed with CO pretreatment at 250 ℃.And,with the increase of pretreatment temperature,iron carbides were formed.The TPD experiment showed that the surface basicity of the catalyst pretreated with CO was stronger than that with H2.Surface carbonaceous deposition caused decrease of CO2 and CO adsorption.Comparing to H2 pretreated catalyst,CO pretreated catalyst has higher selectivity to light olefins.