Oxygen Vacancies Enrichment in Citric Acid‐Assisted Synthesis of Zirconia Supported Ni Catalyst for Highly Selective Hydrogenolysis of 5‐Hydroxymethylfurfural

Abstract 2, 5‐Dimethylfuran (DMF), which is a promising new‐generation liquid biofuel, has attracted widespread attention owing to the sustainability of biomass‐derived energy sources. In this study, a highly dispersed zirconia‐supported nickel catalyst (CA−Ni/ZrO 2 ) was prepared via citric acid‐assisted wetness impregnation for the selective hydrogenolysis of 5‐hydroxymethylfurfural (HMF) to produce DMF. The characterization results confirmed the presence of Zr 3+ species in the mesoporous CA−Ni/ZrO 2 catalyst and the formation of oxygen vacancies during its preparation, which led to the formation of a large number of catalytically active sites for the adsorption and activation of the C=O/C−O groups. Under appropriate reaction parameters, an excellent DMF selectivity of 99.1 % and an HMF conversion of 98.4 % were achieved. A suitable kinetic model revealed that DMF was preferentially formed via the 2,5‐dihydroxymethylfuran intermediate route, although a 5‐methylfurfural route was also observed. Additionally, the interaction between Ni and ZrO 2 significantly affected the stability of the catalyst. This study will provide guidelines for optimizing the catalytic conversion of furan derivatives over heterogeneous catalysts.