Fischer–Tropsch Synthesis Over Cobalt Catalyst Supported On Mesoporous Carbon

Mesoporous carbon material, C₃N₄/SBA-15 and SBA-16 are used as support to prepare catalyst by using incipient wetness impregnation. The catalysts are characterized by X-ray diffraction?XRD?, nitrogen adsorption-desorption, transmission electron microscopy?TEM?, hydrogen temperature programmed reduction?H₂-TPR?, hydrogen temperature programmed desorption?H₂-TPD?, oxygen titration and Laser Raman spectra. The catalytic properties scuh as activity, stability and selectivity for FTS are investigated in a fixed-bed reactor. The main conclusions are as follows:1. Mesoporous carbon material is synthesized at different carbonization temperature using furfuryl alcohol?FA? as carbon precursor and SBA-16 as a hard template. The carbon materials are also reduced under H₂ atmosphere after carbonized at 800 oC under N2 atmosphere.Then, these carbon materials are impregnated with 20 wt. % Cobalt. The results show that the Co species in catalysts are CoO. When the carbonization temperature increasing, the metal-support interaction become weaker, and the reduction temperature of CoO to Co decreased With the increasing of carbonization temperature, the CO conversion increase., Cobalt catalyst has higher CO conversion after by reducing under the hydrogen atmosphere.2. Firstly, SBA-15 are synthesized by using P123 as the soft template, and then supporting different contents of C₃N₄ on SBA-15. These materials are impregnated with 15 wt.% Cobalt. The results show that the Co species in 15%Co/C₃N₄/SBA-15 are CoO, however, the Co species in 15%Co/0.5C₃N₄/SBA-15 and 15%Co/SBA-15 are Co3O4. The TG shows that the decomposition temperature of carbon nitride in 15%Co/C₃N₄/SBA-15 is lower than that in C₃N₄/SBA-15. The TPR indicates that it is harder to reduce for 15%Co/C₃N₄/SBA-15 catalyst compared with 15%Co/SBA-15 and 15%Co/0.5C₃N₄/SBA-15 catalyst. The FTS shows that the catalyst containing carbon nitride has better stability. With the increasing of the content of carbon nitride, olefin selection increase gradually as well.3. SBA-16 with different pore sizes has been synthesized, and the catalysts were prepared by means of incipient wetness impregnation methods. FTS is performed in a tubular fixed-bed reactor. The results show that the catalysts with larger pore leding to larger cobalt cluster size, lower dispersion and higher reducibility. However, the CO conversion is decreasing with the time on stream. The catalysts with smaller pore led to smaller cobalt cluster size, higher dispersion, lower reducibility and CO conversion. Compared with large/small pore catalysts, 15%Co/SBA-16-100 catalyst shows higher CO conversion and better stability.