Nb2O5 promoted Pd/AC catalyst for selective phenol hydrogenation to cyclohexanone

Phenol hydrogenation is a green route to prepare cyclohexanone, an intermediate for the production of nylon 66 and nylon 6. The development of high-performance catalysts still keeps a great challenge. Herein, the activated carbon (AC) was modified with an acidic material Nb 2 O 5 to adjust the microstructure and surface properties of AC, and the influences of the calcination temperature and Nb 2 O 5 content on the catalytic performance of the Pd/AC-Nb 2 O 5 catalysts for the phenol hydrogenation to cyclohexanone were investigated. The Nb 2 O 5 with proper content can be highly uniformly distributed on the AC surface, enhancing the acidity of the Pd/AC-Nb 2 O 5 catalysts with comparable specific surface area and Pd dispersion, thereby improving the catalytic activity. The hybrid Pd/AC-10Nb 2 O 5 -500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10Nb 2 O 5 , which enhances the catalytic activity for the hydrogenation of phenol. Furthermore, the as-prepared Pd/AC-10Nb 2 O 5 -500 catalyst shows good reusability during 7 reaction cycles.