Self-assembly of lignin and MOF as a sustainable carbon-based catalyst for selective hydrodeoxygenation of lignin-derived phenols

Catalytic upgrading of lignin-derived bio-oil to value-added chemicals was of great significance for the utilization of biomass resources. Hydrodeoxygenation (HDO) was widely regarded as a promising pathway for the upgrading of lignin-derived bio-oil. And the key to this issue was to develop effective and sustainable catalysts. In this study, a series of lignin-derived carbon-based highly effective catalysts were synthesized through a one-step hydrothermal method for the catalytic HDO of lignin and its derivatives. Then, lignin-MOF-derived catalysts (nCo-TPA/C-T) were successfully applied to the catalytic HDO of lignin-derived phenolics. All catalysts were characterized in detail to investigate the relationships between physicochemical properties and their catalytic performances. The results demonstrated that the catalyst 2Co-TPA/C-500 exhibited excellent catalytic activity in the conversion of vanillin (VAN) to 2-methoxy-4-methylphenol (MMP) in mild condition (160 °C, 0.5 MPa N₂, and 1 h), without the presence of external hydrogen. The conversion of VAN was up to nearly 100 %, with a high selectivity of MMP (about 94.5 %). It was confirmed that the excellent catalytic performance was related to types of organic ligands, metal-ligand ratio, catalyst calcination temperature, etc. The catalysts also exhibited good activity for other lignin-derived phenols. This work could offer a useful strategy for the catalytic upgrading of lignin-derived phenolics into value-added chemicals.