Zeolite imidazolate framework/g-C3N4 derived Co nanoparticles embedded in nitrogen doped carbon for efficient hydrogenation of phenol

Abstract

The development of a highly effective non-noble metal catalyst for the synthesis of cyclohexanols with high selectivity is very important for the value-added utilization of lignin-derived phenolic compounds. In this paper, a promising Co/NPCN (nitrogen-doped porous carbon nanotubes) catalyst with Co nanoparticles (NPs) embedded in nitrogen-doped carbon for selective hydrogenating of phenol was prepared by introducing an appropriate amount of g-C₃N₄ (graphitic carbon nitride) into the preparation of ZIF-67 (Zeolite imidazolate framework). Characterization results reveal that the introduction of g-C₃N₄ of an appropriate amount reduces the size of Co NPs, improves the specific surface area and pore volume, and facilitates the formation of Co⁰. Full phenol conversion with 100% cyclohexanol selectivity could be achieved at 120 °C, 3 h and 2 MPa H₂ over Co/NPCN. In addition, Co/NPCN presents great stability and scalability of the substrate in the phenol hydrogenation reaction. The DFT (density functional theory) calculations reveal that the parallel adsorption configuration of phenol is preferential, which favors the hydrogenation of phenol to cyclohexanol with high selectivity.