Aqueous Phase Catalytic Conversion of Ethanol to Higher Alcohols over NiSn Bimetallic Catalysts Encapsulated in Nitrogen-Doped Biorefinery Lignin-Based Carbon
Fei Xing, Quanzhou Xu, Lijing Xue, Xiaowen Zhong, Ze Zhang, Kunyi Liu, Xuliang Lin, Tiejun Wang, Yanlin Qin, Xueqing Qiu
Abstract
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.