不同载体对CO_(2)加氢制烯烃Fe基催化剂反应性能的影响  

Effects of different supports on catalytic performance of iron-based catalysts in CO_(2)hydrogenation to olefins

作　　者：潘新安 张鹏 何若南[1] 韩志华 韦慧 徐晓颖 秦绍东 刘意 PAN Xinan;ZHANG Peng;HE Ruonan;HAN Zhihua;WEI Hui;XU Xiaoying;QIN Shaodong;LIU Yi(National Institute of Clean-and-Low-Carbon Energy,Beijing 102211,China;College of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]北京低碳清洁能源研究院,北京102211 [2]北京化工大学化学工程学院,北京100029

出　　处：《燃料化学学报(中英文)》2025年第4期493-503,共11页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(22078006)资助。

摘　　要：采用等体积浸渍法分别制备了以SiO_(2)(Q-30和Q-10)、Al_(2)O_(3)和TiO_(2)为载体的Fe基催化剂,研究了四种不同载体对Fe基催化剂CO_(2)加氢活性和烯烃选择性的影响规律。结合N_(2)吸附-脱附、XRD、HAADF-STEM、TEM、XPS、H_(2)-TPR、CO_(2)-TPD和NH_(3)-TPD等表征方法对催化剂进行了分析。结果表明,以Al_(2)O_(3)为载体的Fe基催化剂活性和烯烃选择性均最高,并具有良好的稳定性。CO_(2)单程转化率为28.2%,烃类产物中全烯烃(C_(2+))选择性达68.1%,长链烯烃(C_(4+))选择性达45.1%。高分散的FeNa/Al_(2)O_(3)催化剂由于适宜的金属-载体相互作用,有效促进了铁物种的还原和碳化;同时具有最强的CO_(2)吸附能力和最多的表面酸性位点,促进了CO_(2)的活化和CO^(*)中间物种的C-C耦合过程。而以两种SiO_(2)为载体的Fe基催化剂由于较弱的还原碳化能力、较低的CO_(2)吸附能力和较少的酸性中心,主要发生了逆水煤气变换和CO_(2)甲烷化反应,在极低的CO_(2)转化率下(~10%),产物主要为CO和甲烷。The combustion of carbon-based fossil fuels(coal,oil and natural gas)for power generation is accompanied by large emissions of anthropogenic CO_(2)into the atmosphere,leading to global climate change and ocean acidification.Direct conversion of CO_(2)and H_(2)via reverse water-gas shift(RWGS)and subsequent Fischer-Tropsch synthesis(FTS)is well-known as a sustainable alternative for the synthesis of olefins,replacing conventional petrochemical process of naphtha streamcracking or separation.The structure and properties of the inert support have significant effects on the activity,selectivity and stability of the catalyst,but there are few reports about the effects of different supports on the active phase formation and olefins selectivity of Fe-based catalysts in CO_(2)hydrogenation.Therefore,the study of the influence of different support on the CO_(2)hydrogenation performance of Fe-based catalysts has important guiding significance for the design and synthesis of efficient catalysts.Herein,the Fe-based catalysts with different supports(Q-30,Q-10,Al_(2)O_(3)and TiO_(2))were prepared by impregnation method,and the effects of supports on the catalytic activity and olefins selectivity in CO_(2)hydrogenation were studied.The catalyst samples were characterized by N_(2)adsorption-desorption,XRD,HAADF-STEM,TEM,XPS,H_(2)-TPR,CO_(2)-TPD and NH_(3)-TPD.The N_(2)adsorption-desorption isotherms of Q-10,Q-30,Al_(2)O_(3)and TiO_(2)support were all classified as type IV by IUPAC.At the same time,there are hysteresis loops in the absorption and desorption curves of these samples,indicating the existence of mesoporous structures.Combined with the reaction data,it can be seen that the specific surface area and pore structure of the support are not regularly correlated with the catalyst activity and olefin selectivity.No XRD diffraction peak attributed to Fe phase was observed in all fresh catalysts.Combined with the results of XPS and STEM-EDX of the fresh catalysts,it can be inferred that this is due to the low content of iron o

关 键 词：CO_(2)加氢 Fe基催化剂 载体 烯烃 酸性位 

分 类 号：O643[理学—物理化学]