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.