Low-valence NbOx-supported Ni3P for furfural hydrogenation and rearrangement to cyclopentanone

The catalytic hydrogenation and rearrangement of furfural to cyclopentanone is of considerable industrial relevance, yet achieving high performance with cost-effective catalysts remains challenging. In this work, we developed a novel NiP 0.33 /NbO x -700 catalyst through a metal phosphidation approach, where nickel phosphide (Ni 3 P) is supported on a low-valence NbO x . Detailed characterization indicates that Ni 3 P sites exhibit superior activity compared to metallic Ni. Phosphidation of the active nickel metal enhances surface acidity, which facilitates the ring-opening step, while the reduced NbO x provides abundant oxygen vacancies. Under mild conditions (130 °C, 2 MPa H 2 , 4 h), the catalyst achieves complete conversion of furfural and a cyclopentanone yield of 94.8%, which is among the best reported values. In situ infrared characterization confirmed that, compared to Ni, Ni 3 P is more favorable for both substrate adsorption and product desorption. Subsequent kinetic studies further revealed that the Ni 3 P species can effectively lower the activation energies of the two key steps in the reaction-namely, the hydrogenation of furfural and the subsequent rearrangement of furfuryl alcohol, thereby facilitating the overall reaction. This study offers fundamental insights into the properties of low-valence NbO x , revealing its unique catalytic features and potential for performance enhancement, thereby providing a new perspective for the rational design of advanced catalysts.