Xu Yao, Zhai Peng, Deng Yuchen, Xie Jinglin, Liu Xi, Wang Shuai, Ma Ding
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering and College of Engineering, and BIC-ESAT, Peking University, Beijing, 100871, P. R. China.
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, P.O. Box 165, Taiyuan, Shanxi, 030001, P. R. China.
Angew Chem Int Ed Engl. 2020 Nov 23;59(48):21736-21744. doi: 10.1002/anie.202009620. Epub 2020 Sep 24.
Mn and Na additives have been widely studied to improve the efficiency of CO hydrogenation to valuable olefins on Fe catalysts, but their effects on the catalytic properties and mechanism are still under vigorous debate. This study shows that Fe-based catalysts with moderate Mn and Na contents are highly selective for CO hydrogenation to olefins, together with low selectivities for both CO and CH and much improved space-time olefin yields compared to state-of-the-art catalysts. Combined kinetic assessment and quasi in situ characterizations further unveil that the sole presence of Mn suppresses the activity of Fe catalysts because of the close contact between Fe and Mn, whereas the introduction of Na mediates the Fe-Mn interaction and provides strong basic sites. This subtle synergy between Na and Mn sheds light on the importance of the interplay of multiple additives that could bring an enabling strategy to improve catalytic activity and selectivity.
锰和钠添加剂已被广泛研究，以提高铁催化剂上一氧化碳加氢制有价值烯烃的效率，但其对催化性能和机理的影响仍存在激烈争论。本研究表明，具有适度锰和钠含量的铁基催化剂对一氧化碳加氢制烯烃具有高度选择性，同时对一氧化碳和甲烷的选择性较低，与现有催化剂相比，时空烯烃产率有显著提高。结合动力学评估和准原位表征进一步揭示，由于铁和锰之间的紧密接触，锰的单独存在会抑制铁催化剂的活性，而钠的引入则调节了铁-锰相互作用并提供了强碱性位点。钠和锰之间的这种微妙协同作用揭示了多种添加剂相互作用的重要性，这可能带来一种提高催化活性和选择性的有效策略。
