Interfacial Engineering of Frustrated Lewis Pairs for Promoting Cellulose-to-Sorbitol Cascade Conversion

Insufficient synergy between hydrolysis and hydrogenation seriously hinders the efficient conversion of insoluble cellulose in biomass utilization. Herein, using tobacco straw-derived lignin to prepare ordered mesoporous carbon (OMC), we report a complex-mediated strategy for constructing a Ni-P-O@Ni_xP/OMC catalyst with tailored P-C-O doped sites and Ni^δ+-P-O^δ- frustrated Lewis pairs (FLPs). Characterizations and DFT results indicate that the P-C-O sites in a P/O-doped OMC support promote H₂O adsorption and polarization, accelerating H₃O⁺ generation for enhanced cellulose hydrolysis. Simultaneously, the Ni^δ+-P-O^δ- FLPs on the Ni_xP surface promote H₂ heterolysis and H₂O dissociation, generating highly active H^δ+/H^δ- and H₃O⁺ species that synergistically enhance hydrolysis and hydrogenation. Benefiting from the spatial coupling of hydrolysis and hydrogenation at the atomic scale, the prepared catalyst achieves an 80% sorbitol yield from cellulose in water at a low Ni loading of 4.5 wt %, along with satisfactory cycling stability. Increasing the Ni content to 8.0 wt % further raises the sorbitol yield to 89.5%, outperforming most reported noble-metal-based catalysts. Finally, a sorbitol yield in excess of 90% is obtained by using the residue after lignin extraction as the substrate. This work establishes a design paradigm for efficient cascade biomass conversion by creating atomic-scale P-C-O sites and Ni^δ+-P-O^δ- FLPs that enable spatially coupled hydrolysis and hydrogenation through tailored electronic structures.