Nickel anchored on enzymatic lignin-doped MOF-derived carbon: A high-performance catalyst for the selective hydrogenation of phenol to cyclohexanol

Exclusive cyclohexanol selectivity was achieved over a lignin-derived Ni catalyst. • Water guide selectivity via competitive adsorption, acting as a green switch. • Bridging biomass valorization and interfacial catalysis using waste enzymatic lignin. A Ni nanoparticle catalyst, Ni@C BDC-EL , was synthesized via one-pot solvothermal method using Ni-BDC as template and nickel source, and enzymatic lignin (EL) as a sustainable carbon dopant. The resulting catalyst delivers outstanding performance in aqueous hydrogenation of phenol under mild conditions (100 °C, 0.5 MPa H 2 , 4 h), attaining > 99% cyclohexanol yield. Experiments, calculations, and characterizations reveal that EL macromolecules co-coordinate with Ni 2 + and BDC in Ni-BDC-EL precursor, forming an interpenetrating network that enhanced framework stability. An optimal BDC:EL ratio yields a nanoflower-like sphere architecture after pyrolysis at 500 °C, featuring a well-tuned pore structure and high specific surface area. This morphology promotes uniform dispersion and confinement of active sites, producing Ni nanoparticles averaging 7.85 nm. DFT indicates preferential planar phenol adsorption on Ni(111) facet favors benzene ring hydrogenation, while in water, the phenolic hydroxyl activation on the Ni 2+ sites is suppressed, steering selectivity to cyclohexanol as the sole product. Download: Download high-res image (173KB) Download: Download full-size image