Study on CaO-promoted Co/AC catalysts for synthesis of higher alcohols from syngas

An alternative CaO-promoted Co/AC catalysts with high selectivity of C-1-C-16 alcohols were synthesized and systematically studied. The catalysts were characterized by means of N-2-physisorption, XRD, H2-TPR, CO-chemisorption and HRTEM. Then the activated catalysts were used in the CO hydrogenation reaction for the alcohols synthesis. Reaction results showed that CaO promoter improved the yield of C-1-C-16 alcohols significantly from 9.9% to 15.0% in comparison with un-promoted Co/AC catalyst. Characterization results indicated that the addition of CaO promoted the formation of hcp metallic Co, which was further liable to conversion into Co2C species. It was suggested that Co2C species was related to synthesis of alcohols. It was found that the appropriate relative ratio of Co2C/Co was beneficial to synthesis of mixed C-1-C-16 alcohols over the CaO-promoted Co/AC catalysts. The synergistic effect of metallic Co nanoparticles and Co2C species, which contact intimately, is responsible for the alcohols synthesis. (C) 2016 Elsevier Ltd. All rights reserved.