A ruthenium-loaded heteroatomic zeolite for selective hydrodeoxygenation reaction in aqueous medium

Catalytic hydrodeoxygenation (HDO) is critical for bio-oil upgrading, yet the selective cleavage of stable C(sp²)–OH bonds in lignin-derived substrates under aqueous conditions remains a persistent challenge. Here, we report a heteroatomic zeolite catalyst, RuFA/SAPO-34-Nb, featuring few-atom Ru clusters on a Nb(V)-modified SAPO-34 framework, which achieves highly efficient HDO of lignin-derived creosol (2-methoxy-4-methylphenol) in water. Under mild conditions (250 °C, 7 bar H2, 24 h), this catalyst delivers quantitative conversion of creosol to toluene (99.2% conversion, 99.6% selectivity), fully preserving the aromaticity of lignin-derived feedstocks—a key requirement for sustainable chemical production. Synchrotron X-ray diffraction, X-ray absorption spectroscopy, and inelastic neutron scattering, combined with theoretical modeling, elucidate the cooperative mechanism: the Nb(V) sites selectively cleave the strong C–O bonds, while the few-atom Ru cluster generates hydrogen species with an exceptionally low rotational barrier (65 cm⁻¹, the lowest reported to date). This synergistic interaction enables the direct and selective HDO of C(sp²)–O bonds without saturation of aromatic ring—a significant advancement in biomass conversion. This work establishes a highly effective strategy for aqueous-phase HDO catalysis and provides a general approach for designing bimetallic zeolite catalysts to convert lignin-derived compounds into high-value aromatic chemicals, advancing sustainable biorefinery processes.