Precise interfacial engineering of ZIF-derived Co–Ni/NPC for highly selective hydrodeoxygenation of vanillin

Ni effectively reduces the surrounding electron density of Co and enriches defects in catalyst. • Ni introduction strengthens adsorption of vanillin and H 2 while facilitates desorption of reaction intermediate. • 4Co-1Ni/NPC achieves complete conversion of vanillin with 100% selectivity towards MMP, outperforming Co/NPC catalyst. • Ni incorporation enhances ability of 4Co-1Ni/NPC to cleave C O bond of intermediate. The development of cost-effective catalysts for the selective hydrodeoxygenation (HDO) of biomass-derived platform molecules is crucial to sustainable biorefining. Herein, a series of Co-Ni bimetallic catalysts supported on N-doped porous carbon were rationally designed via pyrolysis of bimetallic Co-Ni zeolitic imidazolate framework (ZIF) with tunable metal ratios. Comprehensive characterization confirmed that Ni incorporation modulated the electronic structure of Co, promoted metal dispersion, generated abundant defect sites, and enriched the surface concentration of metallic Co 0 and Ni 0 species. The optimal 4Co-1Ni/NPC catalyst exhibited a unique layered architecture, a high surface area, and superior capacity for hydrogen activation. Density functional theory (DFT) calculations revealed that Ni introduction effectively lowered the local electron density of Co, which fundamentally adjusted the adsorption/desorption energetics—strengthening the binding of vanillin and H 2 while facilitating the desorption of the target product 2‑methoxy-4-methylphenol (MMP). Under mild conditions the 4Co-1Ni/NPC catalyst achieved complete vanillin conversion with nearly 100% MMP selectivity, significantly outperforming its monometallic counterparts. Moreover, it demonstrated excellent recyclability over five consecutive runs and broad substrate tolerance toward various lignin-derived aldehydes. The reaction was verified to proceed via 4‑hydroxy‑3‑methoxybenzyl alcohol (HMP), with C–O bond cleavage in HMP identified as the rate-determining step. This work elucidates the synergistic mechanism in Co-Ni bimetallic systems and provides a principled design strategy for developing high-performance, non-noble metal catalysts for selective biomass valorization. Download: Download high-res image (176KB) Download: Download full-size image