Catalytic ketonization of levoglucosan over nano-CeO₂ for production of hydrocarbon precursors

As one of the major products from cellulose pyrolysis, levoglucosan (LG) is highly oxygenated and stubborn, causing serious problems to bio-oil utilization. In this study, catalytic ketonization of LG over nano-CeO₂ was performed in a pyrolyzer-gas chromatography/ mass spectrometry (PY-GC/MS) system to prepare hydrocarbon precursors (principally ketones). Nano-CeO₂ has been proven effective to convert LG into ketones, with the highest selectivity (71.2 %) obtained when CeO₂ to LG ratio was 15:1 (mm³: mg) at 700 °C. When 5% ZrO₂ was loaded on CeO₂ (5% Zr/CeO₂), the selectivity of ketones further increased to 76.0 %, and that of linear compounds in all the ketone products reached 53.9 %. Results from catalyst characterization revealed that 5% Zr/CeO₂ contained an abundance of basic surface sites and redox capacity, thus leading to high ketonization activity. Ketonization of LG possesses significant potential in facilitating the conversion of cellulose into high-quality biofuels in a sustainable way.