Harnessing Atomically Dispersed Cobalt for the Reductive Catalytic Fractionation of Lignocellulose

The reductive catalytic fractionation (RCF) of lignocellulose, considering lignin valorization at design time, has demonstrated the entire utilization of all lignocellulose components; however, such processes always require catalysts based on precious metals or high-loaded nonprecious metals. Herein, the study develops an ultra-low loaded, atomically dispersed cobalt catalyst, which displays an exceptional performance in the RCF of lignocellulose. An approximately theoretical maximum yield of phenolic monomers (48.3 wt.%) from lignin is realized, rivaling precious metal catalysts. High selectivity toward 4-propyl-substituted guaiacol/syringol facilitates their purification and follows syntheses of highly adhesive polyesters. Lignin nanoparticles (LNPs) are generated by simple treatment of the obtained phenolic dimers and oligomers. RCF-resulted carbohydrate pulp are more obedient to enzymatic hydrolysis. Experimental studies on lignin model compounds reveal the concerted cleavage of C alpha-O and C beta-O pathway for the rupture of beta-O-4 structure. Overall, the approach involves valorizing products derived from lignin biopolymer, providing the opportunity for the comprehensive utilization of all components within lignocellulose. An ultra-low loaded, atomically dispersed cobalt demonstrates exceptional catalytic performance in the reductive catalytic fractionation of lignocellulose. Such a process 1) maximizes the theoretical yield of phenolic monomers suitable for synthesizing highly adhesive polyesters, 2) produces phenolic dimers and oligomers feedstocks for preparing lignin nanoparticles, and 3) preserves cellulose and hemicellulose amenable to enzymatic hydrolysis. image