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

摘要: 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。

Abstract: 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.