Nearly 100% selective hydrolysis of pyrolytic sugar over sustainable carbon catalysts enables highly efficient...

The hydrolysis of levoglucosan (LG)-the major component of biomass pyrolysis oil-is the crucial step to bridge pyrolysis and fermentation. This study reports a series of sulfonated carbon catalysts (SCCs) as sustainable Brønsted acids for LG hydrolysis, which exhibit an excellent glucose selectivity over other hydration products (e.g., 5- hydroxymethylfurfural and light oxygenates). Notably, SCCs maintain a LG conversion rate of 95 % and a glucose yield of 90 % afterfour cycles of batch operations. Time-of-flight mass spectrometry and theoretical calculations further clarify the hydrolysis mechanism, as water-derived protons are activated by sulfonate groups of SCCs and hydrolyze LG through CO bond cleavage and hydration. Moreover, SCC-catalyzed hydrolysate is used in fermentation to produce bioethanol, enabling the maximal yield of ∼ 99 %, which is comparable to pure glucose commodity and much efficient than that from the aqueous acid hydrolysis. This study provides a sustainable alternative to mitigate the demand on heterogeneous catalysts for pyrolysis oil upgrading towards net-zero production of biofuels and biochemicals.