Orbital Coupling Over N‐Bridged Zn─Co Atomic Pairs Enables Lignocellulose Valorization

ABSTRACT

Production of monophenols and carbohydrates through reductive catalytic fractionation is the key operation for lignocellulose utilization. Metal utilization can be maximized by single‐atom catalysts, but catalytic performance is limited by the insufficient activation capability of a single site. Here, N‐bridged Zn─Co atomic pairs with compressed Zn─N/Co─N bonds are constructed to enable continuous orbital coupling near the Fermi level, by which the C _β ─O bond of lignin is activated by accepting charge via vacant Co d _xz / d _yz orbitals and the C _α ─OH bond is activated by injecting charge via Zn d _xy orbitals. Hydrogen heterolytic dissociation is also facilitated by the compressed Co─N through polarizing H ₂ to H ^δ− ‐H ^δ+ . Consequently, superior activity is exhibited, by which wood is converted to monophenols with a near‐theoretical yield and carbohydrates with 92.2% retention at 200°C, and a TOF of 3.5 h ⁻¹ is achieved, 6.1 times that of benchmark 5%Ru/C. A scaled‐up operation using the produced phenols as solvent is designed, achieving a high monophenol concentration 85.8 g/L in the resultant liquid and demonstrating excellent industrial potential. A design concept for non‐noble‐metal catalysts at the atomic orbital level is thus provided for lignocellulose biorefining.