Hydrodeoxygenation of Lignin-Derived Phenolic Compounds Catalyzed by NiCo Bimetallic Catalyst Supported on N-Doped Biochar and Al2O3
To achieve efficient conversion of lignin-derived phenolic compounds into high-value hydrocarbon fuels, a series of NiCo bimetallic catalysts with N-doped biochar and Al2O3 composite supports (NiCo/NC-Al2O3) were designed and synthesized. Comprehensive characterizations (XRD, TEM, XPS, H2-TPD) revealed the superior catalytic activity in the hydrodeoxygenation (HDO) of lignin-derived phenolic compounds. The optimized Ni8Co2/NC-Al2O3 catalyst exhibited good metal dispersion and excellent hydrogen dissociation adsorption capacity. Under mild reaction conditions (240°C, 1 MPa H2, 4 h), it achieved complete conversion of guaiacol and 99.9% selectivity to cyclohexane, significantly outperforming monometallic Ni10/NC-Al2O3 and Co10/NC-Al2O3 catalysts. Comparative studies indicated a synergistic effect between Ni and Co, where the introduction of Co effectively promoted aromatic ring hydrogenation and C−O bond cleavage. The catalyst maintained high activity after four reuse cycles, demonstrating outstanding structural stability. This study elucidates the regulatory mechanism of the Ni-Co synergistic effect on catalytic performance, providing new insights for the development of efficient non-noble metal HDO catalysts.