Total chemocatalytic cascade conversion of lignocellulosic biomass into biochemicals

Because of its complexity, selective conversion of lignocellulosic biomass into platform chemicals presents significant challenges. Herein, we converted birch wood into high-yield lignin-derived phenolic monomers and dimers and holocellulose-derived polyols and monocarboxylic acids via a two-step cascade reaction using 0.1 wt% Pd on N-doped carbon (Pd 0.1 /CN x ) and passivated alumina-coated Ni on activated carbon (Ni 2 @Al 2 O 3 /AC) catalysts. The catalytic fractionation of birch sawdust using Pd 0.1 /CN x produced 11.1 wt% monomers, 5.6% dimers, and 63.4 wt% pulp-rich solid (PRS) based on feed weight. The subsequent conversion of PRS over passivated Ni 2 @Al 2 O 3 /AC produced 21.6 wt% C 2 –C 6 polyols and 7.9 wt% monocarboxylic acids. After the whole biomass conversion reaction, the Pd 0.1 /CN x and Ni 2 @Al 2 O 3 /AC catalysts were separated using their different magnetic responses and reused three times without activity loss. The structure–performance relationships of the Pd 0.1 /CN x catalysts synthesized using different methods and effect of passivation on the performance of the Ni 2 @Al 2 O 3 /AC catalyst were analyzed. • Total cascade conversion of wood into biochemicals using two types of catalysts. • High lignin monomer yield of 53.6 C% was achieved over Pd 0.1 /CN x -DP4 during RCF. • Polyols and acids with a yield of 51.1 C% was achieved over passivated Ni 2 @Al 2 O 3 /AC. • Single Pd atom and ultrasmall Pd clusters were effective in the wood fractionation.