CO_2加氢制低碳烯烃的Fe／Silicalite－2催化剂研究──Ⅰ．催化剂性能及反应机理探讨

Study of K-Fe-MnO/Silicalite-2 catalyst for CO_2 hydrogenation to light olefins I. Catalyst performance and reaction mechanism

Ｋ－Ｆｅ－ＭｎＯ／Ｓｉ－２催化剂具有较佳的ＣＯ２加氢合成低碳烯烃性能，并随碱金属钾助剂的添加而明显改善；其ＣＯ２加氢反应具有（１）ＣＯ２＋Ｈ２ＣＯ＋Ｈ２Ｏ和（２）ＣＯ＋（ｍ／２ｎ＋１）Ｈ２１／ｎＣｎＨｍ＋Ｈ２Ｏ两步反应机理；应用该反应机理，解释了ＣＯ２／Ｈ２比、反应温度、反应压力、反应气空速等对Ｋ－Ｆｅ－ＭｎＯ／Ｓｉ－２催化剂ＣＯ２加氢反应性能的影响；探讨了催化剂中Ｋ２Ｏ助剂的作用。

Desirable performance of K-Fe-MnO/Si-2catalyst in CO2 hydrogenation for production of light olefins can be achieved and greatly improved with adding K2O as a promoter. A two-step mechanism is suggested for CO2 hydrogenation to form hydrocarbons, by which the effect of variation in reaction conditions such as temperature, pressure and gas space velocity as well as CO2/H2 ratio on the behavior of the K-Fe-MnO/Si-2 catalyst is explained reasonably. The role of K2O promoter is also discussed.