Metal–Organic Frameworks and Biomass: Mutual Partners on Designing Environmentally Friendly Catalysts for Catalytic Conversion of Lignin-Derived Substances

In this study, a series of puffball carbon-supported catalysts were synthesized to facilitate the hydrodeoxygenation (HDO) of the lignin model compound vanillin (VAN) into 2-methoxy-4-methylphenol (MMP). The Co-ZIF/BC catalyst, prepared by loading ZIF-67 onto puffball carbon support, achieved a VAN conversion rate of 96.28% and a selectivity of 86.57% for MMP under reaction conditions of 240 °C and 1.5 MPa of H₂ for 4 h. Based on the characterization results, it was found that the Co-ZIF/BC catalyst exhibited high crystal defects, a large specific surface area, and mesopore volume, as well as strong Lewis acid sites. Additionally, the Co–N bonds formed between Co nanoparticles and nitrogen increased the electron density on the catalyst surface. The abundant surface Co⁰ species enhanced hydrogen adsorption and dissociation, providing more active sites, which facilitated the activation of reactants and improved the efficiency of the catalytic reaction. The use of abundant and low-cost puffball materials in the preparation of the Co-ZIF/BC catalyst not only reduced production costs but also supported the sustainability of the catalytic process, aligning with the principles of green chemistry.