Fast catalytic transfer hydrogenation of phenol to cyclohexanol over urea modified Ni@CN nanoparticles

Abstract

A series of stable N-doped porous carbon encapsulated Ni nanoparticles (Ni@CN) were prepared via direct pyrolysis of Ni-MOF-74(N) and utilized for the catalytic transfer hydrogenation (CTH) of phenol to cyclohexanol with isopropanol as a hydrogen donor. The prepared catalysts were characterized by means of TG, XRD, BET, SEM, TEM and XPS. The effects of preparation and reaction conditions on the CTH performance were investigated. The results showed that the Ni particles of Ni@CN were smaller than that of Ni@C, which reflected that the doping of nitrogen could improve the dispersion of Ni nanoparticles. Moreover, electrons can be redistributed with N-doping. These two factors contribute to better catalytic activity. The Ni@CN-450 catalyst exhibited 99.3% phenol conversion with 100% cyclohexanol selectivity. Moreover, the catalysts could be recycled and reused easily with the help of a magnet and its catalytic performance did not decrease obviously even after five successive cycles.