Enhanced Fischer-Tropsch synthesis performance using graphene Nanosheets-Supported Cobalt-Ruthenium Nanocatalysts: Comparative study with γ-Alumina and carbon nanotubes supports

Abstract

In this research, graphene Nanosheets (GNS) as Cobalt-Ruthenium Nanocatalysts support have been used in Fischer-Tropsch synthesis. The characterizations of catalysts were evaluated by Fourier-transform infrared spectroscopy (FTIR), Inductively Coupled Plasma (ICP), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Temperature Programmed Reduction (TPR), and Transmission Electron Microscope (TEM). Afterward, the catalysts' activity, selectivity, and performance were assessed in a fixed-bed reactor at 25 bar. The results were compared by changing the catalyst base to γ-alumina (γ-Al2O3) and carbon nanotubes (CNTs). Measurements were performed in the temperature range of 320––340 °C, the gas ratio (H2/CO) of 2, and the gas hourly space velocity of 3 Lh-1gCat.-1. Using GNS as cobalt catalyst support in Fischer-Tropsch synthesis leads to the 64.5 % and 25.9 % increase in the percentage of CO conversion compared to γ-Al2O3 and CNTs, respectively. Additionally, the utilization of GNS support has resulted in an 11.1 % increase in heavy hydrocarbons selectivity of C5+, in comparison to γ-Al2O3, and a 9.5 % increase compared to CNTs. GNS-based synthesized catalyst with 10 wt% of cobalt and 0.1 wt% of ruthenium (catalyst #6) indicates the highest activity of catalyst at 320 °C with 72.3 % selectivity than heavy hydrocarbons C5+.