Lignin carbon-initiated Ni/K/Mo2C catalyst for efficient synthesis of higher alcohols from syngas

Abstract

Bamboo lignin, the principal constituent of non-wood pulping black liquor, is ecologically and environmentally harmful due to its complex molecular structure and stability. Additionally, the syngas-based synthesis of higher alcohols is a desired industrial application, alleviating the dependency on petroleum resources. However, developing highly efficient catalysts with high space–time yield and selectivity towards higher alcohols remains challenging. Herein, for the first time, taking into account the permeable structure of bamboo lignin in paper-making black liquid resulting from cellulose and hemicellulose extraction, porous nano molybdenum carbide was manufactured by designed pretreatment and activation processes of the lignin, which was further doped by the K and Ni additive to create a highly efficient catalyst (Ni/K/Mo2C@LC) for the high alcohols synthesis reaction, yielding a surprising space–time yield of 0.455 g/gcat/h) to alcohol products under the optimal reaction conditions. Control experiments and characterizations were conducted over relevant catalysts, revealing that Ni and K could be integrated to regulate the adsorption property, acidity/basicity, and carbon chain growth ability of the catalysts. Also, the open mesoporous lignin carbon provided larger metal particles, enhancing the hydrogenation ability and better balancing the non-dissociative and dissociative active sites for the high alcohol synthesis reaction. These results provide insights into the structure design of carbide catalysts toward efficiently utilizing industrial lignin and other biomass-derived feedstocks, and the development of an efficient Mo-based catalyst for syngas conversion.