Study of Ce-Cu-Co/CNTs catalysts for the synthesis of higher alcohols and ethanol from syngas

Abstract

A series of Ce-Cu-Co/carbon nanotubes (CNTs) catalysts with different Ce contents were prepared by co-impregnation, and the catalytic performance was investigated for the synthesis of higher alcohols from syngas. The catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), N2 adsorption-desorption isotherms (BET), transmission electron microscopy (TEM), and temperature-programmed desorption of CO (CO-TPD). The results showed that at a Ce content of 3% the catalyst had the highest catalytic activity. The formation rate and selectivity of alcohol reached 696.4 mg∙g-1∙ h-1 and 59.7%, where the mass fraction of ethanol was 46.8% of the total amount of alcohols. The addition of an appropriate amount of Ce facilitated the dispersion of Cu and promoted reduction of the catalysts. It also markedly increased the adsorption capacity for CO, and significantly improved the formation of active sites for alcohols, which is favorable for the catalytic activity and to improve the selectivity of alcohols. Research showed that combining the CuCo-based catalyst, which has high activity and a high ability of carbon chain growth, with the confinement effect of CNTs can result in a narrow distribution of alcohols and significantly improve the selectivity of ethanol.