Hydrogenation of glucose to sorbitol catalyzed by Co supported on coconut-shell active carbon

Abstract

It is of significant importance to develop cost-effective transition metal catalysts for the hydrogenation of glucose to sorbitol. While Ni-based catalysts have been frequently reported, investigations involving Co-based catalysts in this reaction remain relatively limited. Here, a Co catalyst supported on a coconut-shell activated carbon (AC) was prepared and utilized for the first time to produce sorbitol from glucose via aqueous hydrogenation. Characterization results revealed that the Co components were highly dispersed on the AC surface, forming CoO–Co polyvalent complexes incorporating oxygen vacancies and Lewis acids after calcination in N₂ at 500 °C. In contrast, Ni species on the AC surface tend to aggregate into metallic Ni particles. Compared with Ni/AC, the Co/AC catalyst not only demonstrates a superior ability to generate more active H with multiple forms, but also possesses various strengths of Lewis acid sites to activate the CO bond of glucose. Consequently, the Co/AC catalyst exhibited higher activity with 100% selectivity towards sorbitol in the aqueous hydrogenation of glucose under mild conditions of 100 °C and 3 MPa H₂ pressure, showcasing significant potential for the formation of sorbitol from biomass-derived glucose due to its low cost, simple preparation process, and excellent performance in hydrogenation.