Synergy of Single Atoms and Lewis Acid Sites for Efficient and Selective Lignin Disassembly into Monolignol Derivatives

摘要

Lignin is the most abundant aromatic polymer from thenatural andrenewable lignocellulosic biomass resource. Developing highly efficientcatalysts for lignin depolymerization to produce valuable monophenolswith high yield and selectivity remains a desirable but challengingtarget in this field. Here, we design a synergistic catalyst combiningatomically dispersed Mo centers and Al Lewis acid sites on a MgO substrate(Mo1Al/MgO) for the depolymerization of Eucalyptus lignin via the beta-aryl ether bond cleavage. A near-theoreticalmonophenol yield of 46% with an ultrahigh selectivity of 92% for coniferyland sinapyl methyl ether, as well as good cycling durability, wasachieved simultaneously by Mo1Al/MgO in an inert N-2 atmosphere. First-principles calculations and control catalyticexperiments confirmed the synergistic catalysis mechanism betweenMo(1)-O-5 single-atom centers and the neighboringAl Lewis acid sites with the participation of a methanol solvent.This study validates the feasibility of designing better-performingcatalysts with synergistic multiactive sites for the efficient andselective disassembly of complex renewable biopolymers into highlyvalue-added products with lower cost and greater security.