Tuning the mesopore size of lignin-based porous carbon via salt templating for kraft lignin decomposition

A novel and practical CaCl 2 salt templating method is used to tune the pore size of carbon materials from calcium lignosulfonate. In-situ crystalized CaCl 2 particles serve as templates for mesopores and as carbonization substrates. Hierarchical carbons are constructed using coupled SiO 2 spheres and CaCl 2 templates. The SiO 2 spheres improve the pore size assigned to CaCl 2 particles and high CaCl 2 :lignin mass ratios benefit large CaCl 2 crystals to improve the size of mesopores. The porous carbons are used as supports of molybdenum carbide (MoC) with C-C and C-O cleavage activity for Kraft lignin decomposition into aromatic monomers. The results show that MoC over porous carbon supports achieves the highest aromatic yield of 0.716 g/g Kraft lignin and exhibits high stability of aromatic yields. Suitable pore size for lignin macromolecule diffusion significantly enhances the catalytic performance of molybdenum carbide.