Oxygen vacancy and support adsorption synergistic effect in aerobic oxidation of HMF to FDCA: A case study using nitrogen-doped porous carbon supported Bi-CeO₂

Background: The conversion of 5-Hydroxymethylfurfural into high value-added 2,5-furandicarboxylic acid is of great significance for industrial production and people's life. Rationally regulation of oxygen vacancy and reactant adsorption are keys to developing an efficient metal oxide catalyst for aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Method: In this research, nitrogen-doped porous carbon-supported Bi-doped CeO₂ (x%Bi-CeO₂/N-PC_T) catalysts were successfully prepared by co-calcination method. Significant findings: Oxygen vacancy concentration of CeO₂ can be effectively enlarged by Bi-doping, which was strongly related to the catalytic performance. In-situ FTIR and adsorption experiment results showed that the introduction of N-PC_T can enhance the HMF adsorption performance of catalyst. Density functional theory calculation and XPS results proved that the HMF adsorption performance depend on content of graphitic N in N-PC_T, thus effecting the catalytic performance of HMF oxidation. Synergistic effect of oxygen vacancy and HMF adsorption ability can enhance the catalytic performance, the FDCA yield of 10%Bi-CeO₂/N-PC₈₀₀ was about 70 times higher than that of pure CeO₂. 10%Bi-CeO₂/N-PC₈₀₀ as support for Au nanoparticles demonstrated an excellent yield of FDCA (92.8%). This study provides a novel idea for design of CeO₂-based catalyst for oxidation of HMF to high value-added downstream chemicals.