N,O-functionalized and high-temperature-treated carbon nanotubes (N, O, HT-CNTs) were employed to investigate the promotional effects of CNT on Fe catalysts for the Fischer–Tropsch-to-olefins (FTO); particularly, the origin of active sites was explored using multiple in/ex situ techniques. An upward trend in initial activity, olefin selectivity, olefin/paraffin ratio, and chain growth probability is observed in the sequence of O-, N-, and HT-CNT supported catalysts. Unexpectedly, Fe/HT-CNT exhibits superb selectivity of 72.4% to C₂–C₇ olefins, closing to the Anderson–Schulz–Flory (ASF) limit. The defect-rich electron-withdrawing HT-CNT weakens the reducibility of FeO_x and the C₃H₆ adsorption on Fe, in contrast to O-, N-CNT. The defect-anchored Fe/HT-CNT promotes “Fe-C” formation and phase transformation toward έ-Fe_2.2C/ε-Fe₂C, improving CO adsorption and activation. The above merits boost olefin selectivity on Fe/HT-CNT. However, O-CNT abounded with O groups retards the formation and deep carbonization of the active phase, indicating a gradual increase in the yield.

使用N，O功能化和高温处理的碳纳米管（N，O，HT-CNTs）来研究CNT对费托合成烯烃（FTO）的Fe催化剂的促进作用。特别是，使用多种原位/异位技术探索了活性位点的起源。在O-，N-和HT-CNT负载的催化剂序列中观察到了初始活性，烯烃选择性，烯烃/石蜡比和链增长概率的上升趋势。出乎意料的是，Fe / HT-CNT对C ₂ -C ₇烯烃的选择性高达72.4％，接近安德森-舒尔茨-弗洛里（ASF）的极限。富缺陷的吸电子HT-CNT削弱了FeO _x和C ₃ H ₆的还原性与O-，N-CNT相比，Fe的吸附能力强。缺陷锚定的Fe / HT-CNT促进“的Fe-C”的形成和相变朝向έ -铁_2.2 C /ε -铁₂ C，提高CO吸附和活化。上述优点提高了在Fe / HT-CNT上的烯烃选择性。然而，富含O基团的O-CNT阻碍了活性相的形成和深度碳化，表明产率逐渐增加。