LAUSR

Abstract Direct synthesis of higher alcohols by CO hydrogenation is one of the most important processes for the utilization of syngas, but obtaining high selectivity to higher alcohols (C2+–OH) remains a challenge. In this work, a series of gallium-doped activated carbon-supported cobalt catalysts (15Co–xGa/AC, representing 15 wt% Co and x wt% Ga) were developed and they were found to be favorable for enhancing the selectivity to alcohols (SROH). The optimized SROH value reached 30.3 mol% over the 15Co–2.5Ga/AC catalyst, while that was 17.0 mol% over the Ga-free catalyst. The characterization results indicated that the doping of Ga increased the reduction temperature of Co3O4 and modulated the distribution of the surface Co2+ and Co0 species. It was found that the Co2+–Co0 dual active sites were responsible for the formation of alcohols and the enhancement of SROH arose from moderate ratio of Co2+/(Co2+ + Co0). The results revealed that the addition of Ga could be an effective way to elevate the selectivity of higher alcohols by CO hydrogenation.