Aqueous Phase Catalytic Conversion of Ethanol to Higher Alcohols over NiSn Bimetallic Catalysts Encapsulated in Nitrogen-Doped Biorefinery Lignin-Based Carbon

An efficient and stable catalyst to produce higher alcohols with a higher heat value and cetane number and less corrosive to engines from aqueous ethanol is still facing challenges. Here, a novelty of NiSn bimetallic catalysts encapsulated in a nitrogen-doped lignin-based carbon material (NiSn@NC) was prepared by modified biorefinery lignin and further precisely coordinated with metal ions to form a lignin-metal supramolecular material followed by in situ calcining. Results showed that the optimized Ni20Sn1@NC catalyst exhibited a superior ethanol conversion (68.5%), a C4+ higher alcohol yield of 31.8%, and a ratio of iso to normal alcohol of 0.52. Moreover, it also exhibited excellent stability even after four-cycle runs. Structural analysis revealed that the Sn/N-doping lignin-based carbon material improved the Ni dispersion and basic site density, which adjusted efficiently the electronic structure of the metallic active site. Therefore, the NiSn@NC bimetallic catalysts showed satisfactory conversion and stability of aqueous ethanol upgrading to C4+ higher alcohols.