Enhanced cellobiose hydrolysis over fluorine-modulated carbon-based solid acid catalysts

Abstract

In this study, we synthesized novel carbon-based solid acid catalysts using plasma engineering by integrating sulfonic acid groups as primary catalytic sites and supplemented these with fluorine-containing, chlorine-containing, and other oxygenated functional groups (OFGs). Notably, the catalyst with the fluorine-containing functional groups results superior glucose yield (58.2 %) than that containing only OFGs (37.6 %). Theoretical analysis of the reaction energetics revealed that the cleavage of cellobiose's 1,4-O linkage to form two glucose molecules potentially constitutes the rate-determining step (RDS) in cellobiose hydrolysis. The reaction energy for this RDS was found to increase in the sequence of G–SO3H–F, G–SO3H–Cl, and G-SO3H, consistent with the experimentally obtained catalytic activity trends. Through extensive characterization, including textural analysis, surface chemistry, and density functional theory calculations, we identified that the –F groups are the key to strengthening cellulose–catalyst interactions. This study is the first study to demonstrate the potential of fluorine-modulated carbon-based solid acid catalysts for upgrading cellulosic biomass to value-added compounds.