Strong interaction between Fe and Ti compositions for effective CO_(2)hydrogenation to light olefins  

FeTi强相互作用促进CO_(2)高效加氢制低碳烯烃

作　　者：Hao Liang Shunan Zhang Ruonan Zhang Haozhi Zhou Lin Xia Yuhan Sun Hui Wang 梁昊;张书南;张若楠;周浩志;夏林;孙予罕;王慧(上海科技大学2060研究院,低碳复合能源工程科学实验室,上海201203;中国科学院上海高等研究院,中科院低碳转化科学与工程重点实验室,上海201210)

机构地区：[1]Institute of Carbon Neutrality,ShanghaiTech University,Shanghai 201203,China [2]CAS Key Laboratory of Low-Carbon Conversion Science and Engineering,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China

出　　处：《Chinese Journal of Catalysis》2025年第4期146-157,共12页催化学报(英文)

基　　金：国家重点研发项目(2022YFA1504800);国家自然科学基金(22308215,22478409,22108289,22279158);中海油化工与新材料研究院研究经费(YJSCZX07956YJ).

摘　　要：Fe-based catalysts are widely used for CO_(2)hydrogenation to light olefins(C_(2–4)=);however,precise regulation of active phases and the balance between intermediate reactions remain significant challenges.Herein,we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions,modulating the Fe_(3)O_(4)and Fe_(5)C_(2)contents.Enhanced interaction leads to an increased Fe_(5)C_(2)/Fe_(3)O_(4)ratio,which in turn enhances the adsorption of reactants and intermediates,promoting CO hydrogenation to unsaturated alkyl groups and facilitating C–C coupling.Furthermore,the strong Fe-Ti interaction induces the preferential growth of Fe_(5)C_(2)into prismatic structures that expose the(020),(–112),and(311)facets,forming compact active interfacial sites with Fe_(3)O_(4)nanoparticles.These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions.The optimized 3K/FeTi catalyst with the highest Fe_(5)C_(2)/Fe_(3)O_(4)ratio of 3.6 achieves a 52.2%CO_(2)conversion rate,with 44.5%selectivity for C2–4=and 9.5%for CO,and the highest space-time yield of 412.0 mg gcat^(–1)h^(–1)for C_(2–4)=.低碳烯烃(C_(2–4)=)是生产塑料、纤维等化学品的重要原料,具有广泛的应用和巨大的需求.传统的低碳烯烃生产工艺需要消耗大量化石资源并排放大量CO_(2),随着未来石油资源的紧缺,无法满足逐渐增长的低碳烯烃需求和环保要求.在全球碳排放量不断增加的背景下,以CO_(2)为原料,利用CO_(2)加氢制低碳烯烃是一条具有经济和社会效益的绿色技术路线.Fe基催化剂被广泛用于CO_(2)加氢制低碳烯烃.然而,实现活性相的精确调控和串联反应之间的高效协同仍存在巨大挑战.因此,利用金属相互作用以实现Fe基催化剂的活性相调控和性能提升是本文的主要思路.本文通过调控还原条件和Fe/Ti比,成功调节了FeTi相互作用以及Fe_(3)O_(4)/Fe_(5)C_(2)比.气氛还原性较弱时,反应后催化剂主要由FeTi固溶体(Fe_(2)TiO_(5)和FeTiO_(3))组成;引入CO还原后,渗碳作用增强,促进了Fe_(3)C相的生成;H_(2)还原温度为600°C时出现FeO相,表明还原性的提高;升至800°C时,Fe_(2)TiO_(5)和FeTiO_(3)消失,出现Fe_(3)O_(4),α-Fe和Fe_(5)C_(2)相,这表明FeTi固溶体影响着Fe物相的还原和碳化.进一步调控Fe/Ti比,拉曼光谱及H_(2)程序升温还原等结果表明,FeTi存在相互作用且在Fe/Ti为4/1时最强.原位X射线衍射结果进一步验证了FeTi相互作用的存在,且FeTi强相互作用可以抑制关键活性相Fe_(3)O_(4)的形成和还原,从而调节了Fe_(3)O_(4)和Fe_(5)C_(2)的含量.穆斯堡尔谱定量分析显示,3K/FeTi(4/1)催化剂具有最高的Fe_(5)C_(2)/Fe_(3)O_(4)比(3.6),进一步证实了FeTi强相互作用对活性相比例的调控作用.透射电镜结果表明,FeTi强相互作用促进了Fe_(5)C_(2)取向生长为棱柱状结构,主要暴露(0_(2)0),(–112)和(311)晶面,并与Fe_(3)O_(4)形成紧密的界面位点,从而增强了逆水气变换(RWGS)和费托合成(FTS)反应之间的协同耦合.原位漫反射红外光谱实验表明,3K/FeTi催化剂遵循RWGS+FTS机理,对�

关 键 词：CO_(2)hydrogenation Light olefins Strong Fe-Ti interaction Fe_(5)C_(2) Active phase modulation 

分 类 号：O643.3[理学—物理化学]