Characterization of Cobalt Catalysts on Biomass-Derived Carbon Supports

Abstract

Cobalt catalysts are known to have a high activity and selectivity in the Fischer–Tropsch reaction converting synthesis gas to higher hydrocarbons (C5+). These catalysts have been supported by different porous materials. Porous carbon materials like activated carbon (AC) have physical and chemical surface properties that affect the preparation of supported metal catalysts and can easily be tailored. In this study, AC was produced by carbonization and steam activation of lignin, a waste fraction from the Kraft pulping process. A series of Co/AC-catalysts was produced and characterized by several techniques. According to the results, tailored properties (high surface area, mesoporosity) were obtained for carbon supports. Further, ash content could be reduced by acid treatment. Co/AC-catalysts prepared by ultrasonic assisted impregnation have high metal dispersion (10.1%). It was also observed that small metal particles were difficult to reduce, but acid (HNO3) treatment has a positive effect on reduction temperatures.