Hydrogenolysis of Lignin and C–O Linkages Containing Lignin-Related Compounds over a Macroporous Silicalite-1 Array-Supported Ru-Ni Phosphide Composite

Hydrogenolysis via targeted depolymerization of C–O linkages is a techno-economic beneficial process for converting lignin into highly valuable chemicals and clean fuels. In this work, a macroporous silicalite-1 (S-1) array-supported Ru-Ni metallic phosphide composite (Ru-Ni12P5/S-15) was prepared as a catalyst and hydrogenolysis activity under relative mild conditions was investigated using a series of compounds containing ether linkages as lignin-related model compounds. The Lewis acid sites originating from the unreduced Ru species and the macroporous geometry of S-1 significantly influenced hydrogenolysis activity and product selectivity. Analysis of the mechanism demonstrated that both the aryl ether and aliphatic ether linkages were directly hydrogenated over Ru-Ni12P5/S-15. 2D-HSQC-NMR spectroscopy demonstrated that the ether linkages of lignin were efficiently cleaved by Ru-Ni12P5/S-15. Furthermore, the obtained liquid hydrogenolysis products are high value-added chemicals used for pharmaceutical production and can be facilely tuned via the reaction conditions.