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 Nb2O5 to adjust the microstructure and surface properties of AC, and the influences of the calcination temperature and Nb2O5 content on the catalytic performance of the Pd/AC-Nb2O5 catalysts for the phenol hydrogenation to cyclohexanone were investigated. The Nb2O5 with proper content can be highly uniformly distributed on the AC surface, enhancing the acidity of the Pd/AC-Nb2O5 catalysts with comparable specific surface area and Pd dispersion, thereby improving the catalytic activity. The hybrid Pd/AC-10Nb2O5-500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10Nb2O5, which enhances the catalytic activity for the hydrogenation of phenol. Furthermore, the as-prepared Pd/AC-10Nb2O5-500 catalyst shows good reusability during 7 reaction cycles.