Enhancing the ketonization efficiency of biomass through selective conversion of furanic compounds

Catalytic ketonization of biomass is an effective approach for the deoxygenation of bio-oil and the enrichment of high-purity ketone products. However, the bio-oil contains a large amount of furanic components with oxygenated side groups (e.g., furfural, furfuralcohol, etc.), which severely hinders the efficiency of the ketonization reaction. In response to this challenge, this study employed Pd-based catalysts for selective conversion of furfural into "keto-friendly" components, thereby mitigating their inhibitory effects. Initially, three morphologies of CeO2 (the main catalyst for ketonization) were selected to investigate their influence on furfural conversion. It was found that the products were mainly furfural (exceeding 86 %), with only up to approximately 13 % of "keto-friendly" products (mainly furans) detected, indicating that pure CeO2 exhibits a weak catalytic effect on the effective conversion of furfural. Compared with pure CeO2, the yield of "keto-friendly" products increased significantly when 1 wt% Pd was loaded, demonstrating the excellent catalytic performance of Pd in the effective conversion of furfural. Co-doping of Pd and Zr (5 wt%) on CeO2 further increased the "keto-friendly" products to 66 %, suggesting a synergistic effect of Pd and Zr. Mechanism analysis revealed that Pd promotes the formation of furans and benzenes by enhancing the decarbonylation of furfural and subsequent furan ring opening reactions, while the competing carbonyl hydrogenation pathway is weakened. The findings of this study will be beneficial for enhancing the biomass ketonization conversion, thereby providing valuable references for the high-value utilization of biomass.