J. He,X.-H. Lu,Y. Shen,R. Jing,R.-F. Nie,D. Zhou,Q.-H. Xia
Cyclohexanol is an excellent starting material for fuel production, but direct selective hydrogenation of phenol to cyclohexanol under mild conditions is a challenge. Herein we report a catalyst made of Ni nanoparticles supported on high-surface silica, which is highly active for selective formation of cyclohexanol under 1.0 Mpa pressure of hydrogen in aqueous medium without additives. Conversion of 100 mol% and selectivity up to 100% are achieved within 4 h and 1.0 MPa H 2 . Some factors such as the type of the source of silica, the loading of Ni, the reaction temperature and time, the H 2 pressure play important roles in controlling the selective hydrogenation. The generality of the 10%Ni/SiO 2 -1 catalyst for this reaction is demonstrated by selective hydrogenation of other hydroxylated aromatic compounds as well.
Under mild conditions (near-neutral aqueous solutions, room temperature , and atmospheric pressure), an attractive electrolyte was expanded for splitting water and three novel oxygen-evolution catalysts (Co-C i , Ni-C i , Ag-C i ) were generated. The Co-C i catalyst showed a high oxygen-evolution rate (24.42 μmol h −1 ), a low oxygen-evolution overpotential (395 mV) and excellent stability. In addition, the non-amorphous Ag-C i catalyst, different from reported catalyst, was generated. The catalyst has been further characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS).