Hierarchical meso- and macroporous carbon from lignin for kraft lignin decomposition to aromatic monomers

摘要

In this study, lignosulfonate is converted to hierarchical carbon materials via templating methods, which are used as supports of molybdenum carbide catalysts for Kraft lignin decomposition to aromatic monomers. The results show that hierarchical carbon materials with micropores, mesopores of about 8 nm, and macropores of about 400 nm are obtained from calcium and sodium lignosulfonates using coupled SiO2+F127 templates with high ash-free carbon yields of about 50 %. The F127 template tends to assemble on SiO2 surface along with radial direction to form ordered meso-/macroporous structure of the carbon materials. The 8-Mo2C supported on the hierarchical carbon material exhibits high catalytic performance with aromatic yield of 0.586 g/g Kraft lignin, and the BTX (benzene, toluene, and xylene) components and BTX-derived alcohols donate 21 % and 32 % of the aromatics, respectively. The mesopores benefit the accessibility of lignin fragments to active sites and interconnection between macropores, and the macropores enhance the impregnation of highly-dispersed nano 8-Mo2C particles into pore structures. The hierarchical carbon materials from pulping waste lignin shows potential for macromolecular lignin decomposition.