Cao Dong-Bo, Zhang Fu-Qiang, Li Yong-Wang, Wang Jianguo, Jiao Haijun
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, People's Republic of China.
J Phys Chem B. 2005 Jun 2;109(21):10922-35. doi: 10.1021/jp050940b.
Density functional theory calculations have been carried out on the CO/H2 coadsorption on the (001), (110), and (100) surfaces of Fe5C2 for the understanding of the Fischer-Tropsch synthesis (FTS) mechanism. The stable surface species changes with the variation of the H2 and CO coverage. Along with dissociated hydrogen and adsorbed CO in 2-, 3-, and 4-fold configurations, methylidyne (C(s)H) (C(s), surface carbon), ketenylidene (C(s)CO), ketenyl (C(s)HCO), ketene (C(s)H2CO), and carbon suboxide (C(s)C2O2) are computed as thermodynamically stable surface species on Fe5C2(001) and Fe5C2(110) containing both surface iron and carbon atoms. These surface carbon species can be considered as the preliminary stages for FTS. On Fe5C2(100) with only iron atoms on the surface layer, the stable surface species is dissociated hydrogen and CO with top and 2-fold configurations. The bonding nature of these adsorbed carbon species has been analyzed.
为了理解费托合成（FTS）机理，对Fe5C2的（001）、（110）和（100）表面上的CO/H2共吸附进行了密度泛函理论计算。稳定的表面物种随H2和CO覆盖度的变化而变化。除了以二倍、三倍和四倍构型存在的解离氢和吸附CO外，亚甲基（C(s)H）（C(s)，表面碳）、乙烯酮（C(s)CO）、乙烯酮基（C(s)HCO）、乙烯酮（C(s)H2CO）和二氧化三碳（C(s)C2O2）被计算为在同时含有表面铁和碳原子的Fe5C2(001)和Fe5C2(110)上热力学稳定的表面物种。这些表面碳物种可被视为费托合成的初始阶段。在表面层仅含铁原子的Fe5C2(100)上，稳定的表面物种是具有顶位和二倍构型的解离氢和CO。已对这些吸附碳物种的键合性质进行了分析。
