Alumina Coated Silica Nanosprings (NS) Support Based Cobalt Catalysts for Liquid Hydrocarbon Fuel Production From Syngas

Abstract

The effects of Al₂O₃ coating on the performance of silica nanospring (NS) supported Co catalysts for Fischer-Tropsch synthesis (FTS) were evaluated in a quartz fixed-bed microreactor. The Co/NS-Al₂O₃ catalysts were synthesized by coating the Co/NS and NS with Al₂O₃ by an alkoxide-based sol-gel method (NS-Al-A and NS-Al-B, respectively) and then by decorating them with Co. Co deposition was via an impregnation method. Catalysts were characterized before the FTS reaction by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction, transmission electron microscopy, temperature programmed reduction, X-ray photoelectron spectroscopy, differential thermal analysis and thermogravimetric analysis in order to find correlations between physico-chemical properties of catalysts and catalytic performance. The products of the FTS were trapped and analyzed by GC-TCD and GC-MS to determine the CO conversion and reaction selectivity. The Al₂O₃ coated NS catalyst had a significant affect in FTS activity and selectivity in both Co/NS-Al₂O₃ catalysts. A high CO conversion (82.4%) and Σ > C₆ (86.3%) yield were obtained on the Co/NS-Al-B catalyst, whereas the CO conversion was 62.8% and Σ > C₆ was 58.5% on the Co/NS-Al-A catalyst under the same FTS experimental condition. The Co/NS-Al-A catalyst yielded the aromatic selectivity of 10.2% and oxygenated compounds.