Characterization of CoCu- and CoMn-Based Catalysts for the Fischer–Tropsch Reaction Toward Chain-Lengthened Oxygenates
Characterization of CoCu- and CoMn-Based Catalysts for the Fischer–Tropsch Reaction Toward Chain-Lengthened Oxygenates
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DOI：
10.1007/s11244-018-0938-x
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发表时间：
2018-04
影响因子：
3.6
通讯作者：
J. Voss;Y. Xiang;Greg Collinge;D. Perea;L. Kovarik;Jean-Sabin McEwen;N. Kruse
中科院分区：
文献类型：
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作者：
J. Voss;Y. Xiang;Greg Collinge;D. Perea;L. Kovarik;Jean-Sabin McEwen;N. Kruse
面对日益枯竭的石油储备，对可持续能源供应的需求重新点燃了费托合成技术的重要性。目前，FT工艺主要用于生产合成柴油类燃料和润滑油的工业规模。最近，人们探索了将CO加氢生成含氧物的可能性，而不仅仅是碳氢化合物。我们开发了一系列通过草酸盐共沉淀法制备的CoCuMn和CoMnK催化剂，这些催化剂能够以理想的选择性生成含氧物。经氢气辅助热分解生成的混合金属Co1Cu1Mn1草酸盐，催化剂自然呈现钴核-铜壳结构，Mn5O8分散在催化剂纳米颗粒中，原子探针层析(APT)结果表明。通过佐证密度泛函理论计算和实验证据，我们认为在实时反应条件下，CO和H_2反应物诱导结构变化形成催化活性相。APT研究还表明，Co4Mn1K0.1催化剂后反应中含有Co/C比为2/1的碳化钴相。锰和钾只存在于颗粒的最外层。研究发现，两种催化剂在反应前后均含有Mn5O8氧化相，这是由于这两种催化剂对含氧物具有较高的活性。
The need for a sustainable energy supply in the face of depleting oil reserves has reignited the importance of Fischer–Tropsch (FT) synthesis technology. Presently, the FT process is practiced at the industrial scale to predominately produce synthetic diesel-type fuels and lubricants. More recently, the possibility of hydrogenating CO toward oxygenates, and not just hydrocarbons, has been explored. We have developed a series of CoCuMn and CoMnK catalysts prepared via the oxalate co-precipitation route that are capable of forming oxygenates with desirable selectivity. Upon H2-assisted thermal decomposition of the resultant mixed metal Co1Cu1Mn1oxalates, catalysts naturally exhibited a cobalt core–copper shell configuration with Mn5O8dispersed throughout the catalyst nanoparticle as determined via Atom Probe Tomography (APT). We suggest structural changes are induced by the CO and H2reactants to form the catalytically active phase under real-time reaction conditions as demonstrated by corroborative Density Functional Theory calculations and experimental evidence. APT studies also show that a Co4Mn1K0.1catalyst post reaction contained a cobalt carbide phase as determined from a Co/C ratio of 2/1. Manganese and potassium were found only in the outermost part of the particle. Both catalysts were found to contain the presence of a Mn5O8oxidic phase before and post reaction which we attribute to the high activity toward oxygenates of these two catalysts.