Zeolite catalysts for the valorization of biomass into platform compounds and biochemicals/biofuels: A review

The catalytic upgrading of biomass into high-value biochemicals and biofuels has been considered as a promising strategy for the efficient utilization of biomass energy and has received increasing attention. Levulinic acid (LA) and 5-hydroxymethylfurfural (HMF), derived from biomass, are two well-known biobased platform molecules. A variety of value-added biochemicals and biofuels can be obtained from LA and HMF to replace the corresponding petroleum products. Zeolites with high stability and excellent tunability (mainly acid properties and porous structure) have shown remarkable catalytic performance in biomass valorization and can be used as a promising heterogeneous catalyst for targeted conversion of biomass. This review not only provides a comprehensive overview of recent advances on zeolite-catalyzed biomass conversion to LA and HMF, but also systematically summarizes the latest achievements on the production of valuable derivatives of LA and HMF over zeolite. The topics mainly focus on the modification methods, active sites, structures and catalytic mechanisms of zeolites. The synthesis or modification methods of zeolites have major impact on their active sites and structures, which further influence the catalytic activity and reaction mechanisms. Zeolite design and corresponding catalytic mechanism research will be necessary to facilitate the valorization of biomass. Future efforts on zeolite-catalyzed biomass valorization are also proposed.