Direct one-pot synthesis of ordered mesoporous carbons from lignin with metal coordinated self-assembly

Abstract

Conventional soft template methods for the synthesis of ordered mesoporous carbons (OMCs) use unsustainable, toxic and carcinogenic phenolic compounds as carbon precursors and aldehydes as crosslinkers. Lignin is a potential carbon precursor for OMC production, but its direct use as a carbon precursor has not been possible. Herein, a protocol is developed for the direct one-pot synthesis of OMCs using lignin from agricultural waste sources (walnut shell, macadamia nut shell, and tobacco stem) as a sole carbon precursor through coordinated interactions between lignin functional groups and metal ligands via classical solvent evaporation induced self-assembly (EISA). The protocol is demonstrated for the one-pot synthesis of metal oxide- or elemental metal-linked OMCs (defined as M#OMCs) using many different metal ions (Ni²⁺, Mg²⁺, Fe³⁺, Co₂⁺, Zn²⁺, La³⁺, and Ce³⁺) that form well-ordered mesoporous structures having uniform metal dispersion. As one application, Ni#OMC is shown to effectively catalyze biomass hydrogenation, transfer hydrogenation and isomerization reactions. The protocol developed for OMC materials from lignin is expected to have wide applications in catalysis, adsorption, sensor, drug delivery and energy storage fields.