Fischer–Tropsch Synthesis: Study of Different Carbon Materials as Cobalt Catalyst Support

Abstract

In this work, cobalt Fischer–Tropsch synthesis (FTS) catalyst supported on various carbon materials, i.e., carbon nanotube (CNT), activated carbon (AC), graphene oxide (GO), reduced graphene oxide (rGO), and carbon nanofiber (CNF), were prepared via impregnation method. Based on TGA, nitrogen physisorption, XRD, Raman spectroscopy, H2-TPR, NH3-TPD, ICP, SEM, and TEM characterization, it is confirmed that Co3O4 particles are dispersed uniformly on the supports of carbon nanotube, activated carbon and carbon nanofiber. Furthermore, the FT catalyst performance for as-prepared catalysts was evaluated in a fixed-bed reactor under the condition of H2:CO = 2:1, 5 SL·h−1·g−1, 2.5 MPa, and 210 °C. Interestingly, the defined three types of carbon materials exhibit superior performance and dispersion compared with graphene oxide and reduced graphene oxide. The thermal stability and pore structure of the five carbon materials vary markedly, and H2-TPR result shows that the metal–support interaction is in the order of Co/GO > Co/CNT > Co/AC > Co/CNF > Co/rGO. In brief, the carbon nanofiber-supported cobalt catalyst showed the best dispersion, the highest CO conversion, and the lowest gas product but the highest heavy hydrocarbons (C5+) selectivity, which can be attributed to the intrinsic property of CNF material that can affect the catalytic performance in a complicated way. This work will open up a new gateway for cobalt support catalysts on various carbon-based materials for Fischer–Tropsch Synthesis.

Keywords

• Fischer–Tropsch synthesis
• coal-to-liquids
• gas-to-liquids
• carbon nano-materials
• cobalt catalyst support
• carbon nanofiber