Weak-Acid Sites Catalyze the Hydrolysis of Crystalline Cellulose to Glucose in Water: Importance of Post-Synthetic Functionalization of the Carbon Surface

The direct hydrolysis of crystalline cellulose to glucose in water without prior pretreatment enables the transformation of biomass into fuels and chemicals. To understand which features of a solid catalyst are most important for this transformation, the nanoporous carbon material MSC-30 was post-synthetically functionalized by oxidation. The most active catalyst depolymerized crystalline cellulose without prior pretreatment in water, providing glucose in an unprecedented 70% yield. In comparison, virtually no reaction was observed with MSC-30, even when the reaction was conducted in aqueous solution at pH 2. As no direct correlations between the activity of this solid-solid reaction and internal-site characteristics, such as the beta-glu adsorption capacity and the rate of catalytic hydrolysis of adsorbed beta-glu strands, were observed, contacts of the external surface with the cellulose crystal are thought to be key for the overall efficiency.