Pd-Decorated Hierarchically Porous Carbon Nanofibers for Enhanced Selective Hydrogenation of Phenol

Aiming at the design and preparation of high-efficiency catalysts for the selective hydrogenation of phenol, the hierarchically porous Pd@CNF catalysts were fabricated by oxygen-activating ZIF-67/PAN composite nanofibers with O2 as the oxidant during high-temperature pyrolysis, followed by acid etching and Pd loading. Appropriate initial oxygen concentration and Co2+ molar concentration are conducive to the fabrication of hierarchically porous carbon nanofibers (CNFs) with a high mesopore and macropore ratio, increased ether-type oxygen content, and good one-dimensional (1D) morphology, which enhance the dispersion and anchoring of Pd, increase the strength of basic sites and H2 adsorption, and improve the mass transfer and dispersibility in cyclohexane. The corresponding catalyst Pd@CNFs-0.1–0.2 exhibits excellent phenol hydrogenation performance with a turnover frequency value of 66.6 h–1, which is 6.3 times that of Pd@CNFs-0.1–1 and 2.4 times that of Pd@CNFs-0.1–0. Furthermore, the 1D morphology of Pd@CNFs-0.1–0.2 enables the rapid recovery and recycling of the catalyst. This work provides a new direction for the development of efficient and easy-to-recover phenol selective hydrogenation catalysts.