Accurate location of Ni and W active sites in hierarchical zeolite catalyst for the conversion of cellulose to alcohols

Abstract

The process of converting cellulose into short-chain alcohols is a critical component of biomass valorization. In this study, we utilized an anion-cation co-directed hydrothermal method and wet impregnation to synthesize a hierarchical MFI zeolite with isolated Ni and W sites. We employed linear correlation analysis to evaluate the influence of pore size, site accessibility, and acidity on product selectivity. Balancing hydrogenation and acidic sites on the catalyst enhanced retro-aldol condensation and hydrogenation during cellulose conversion. Surface acidic sites accelerated glucose retro-aldol condensation, while micropore acidic sites aided in ethylene glycol hydrogenolysis. The close proximity of Ni and W facilitated high selectivity and yield of ethanol through bimetallic synergy. This research presented a novel strategy for preparing hierarchical zeolites with isolated metal sites and provides clarity on the cooperative roles of active sites in Ni-W bimetallic catalysts for cellulose conversion.