Hydrodepolymerization of lignin with Ni supported on active carbon catalysts reduced at different temperatures.

Various Ni supported on active carbon (Ni/AC) catalysts were acquired by reduced at different temperatures, among which Ni/AC-500 possesses the smallest particle sizes of metallic Ni species, favoring to more active sites exposed on the catalyst surface, and the suitable content of metallic Ni0, implying the high hydrogenolysis activity obtained. Additionally, the highest mesoporous volume of Ni/AC-500 promotes the diffusion of large molecules from lignin depolymerization. Therefore, Ni/AC-500 exhibits the higher lignin conversion and yields of liquid bio-oil and monomers, but the lower yield of bio-char in lignin hydrodepolymerization due to its higher hydrogenolysis activity compared with other catalysts. [Display omitted] • The various Ni/AC catalysts were acquired via the reduction at the different temperatures. • The smaller particle sizes of metal phase were obtained on Ni/AC-500 catalyst. • The content of Ni0 species enhanced with an elevation of the reduction temperature. • Ni/AC-500 catalyst exhibited the highest yields of bio-oil and monomers among all catalysts. [ABSTRACT FROM AUTHOR]