首页分享 Role of alkali metal in maintaining iron integrity during direct CO2 hydrogenation,Chemical Engineering Journal

Role of alkali metal in maintaining iron integrity during direct CO2 hydrogenation,Chemical Engineering Journal

来源：花匠小妙招时间：2024-12-29 20:58

Iron catalysts have been extensively investigated for the direct hydrogenation of CO2 into light olefins and long-chain hydrocarbons. However, rapid catalyst deactivation is caused by the reoxidation of iron carbides to iron oxides by water. In this study, we developed a highly stable iron catalyst to produce high-yield liquid hydrocarbons (C5+). The presence of excess Na (20 wt%) as a promoter in the iron-aluminum oxide (FeAlOx) catalyst facilitated the formation of highly aggregated, highly crystalline metallic iron particles during reduction, which in turn produced large Hägg carbide core-Fe3O4/AlOx shell particles during CO2 hydrogenation. Excess Na maintained the integrity of these core-shell particles over 2000 h on stream, resulting in a very low C5+ yield decay rate (0.005 % h−1). Thus, Na was proposed to act as a structural promotor that maintains the integrity of iron domains during direct CO2 hydrogenation by suppressing particle pulverization and water reoxidation.

中文翻译：

碱金属在直接 CO2 加氢过程中保持铁完整性的作用

铁催化剂在将 CO2 直接加氢成轻烯烃和长链烃方面已得到广泛研究。然而，催化剂的快速失活是由水将碳化铁再氧化为氧化铁引起的。在这项研究中，我们开发了一种高度稳定的铁催化剂来生产高产率的液态烃（C5+）。铁铝氧化物（FeAlOx）催化剂中过量的 Na （20 wt%）作为促进剂的存在促进了还原过程中高度聚集、高度结晶的金属铁颗粒的形成，这反过来又在 CO2 加氢过程中产生了大的 Hägg 碳化物核心 Fe3O4/AlOx 壳颗粒。过量的 Na 在 2000 h 的流中保持了这些核壳颗粒的完整性，导致非常低的 C5+ 产率衰减率（0.005 % h-1）。因此，Na 被提议作为一种结构促进剂，通过抑制颗粒粉碎和水再氧化，在直接 CO2 加氢过程中保持铁畴的完整性。