Improved Hydrodeoxygenation of Phenol to Cyclohexane on NiFe Alloy Catalysts Derived from Phyllosilicates

Graphical A phyllosilicate-derived NiFe/SiO 2 catalyst with both metallic Ni and NiFe alloy active sites prepared by ammonia-evaporation method shows excellent intrinsic activity in the hydrodeoxygenation of phenol to cyclohexane. A phyllosilicate-derived NiFe/SiO 2 catalyst (NiFe/SiO 2 −AE) was successfully prepared by the ammonia evaporation method and applied in the hydrodeoxygenation of phenol to cyclohexane. Another two catalysts were also prepared for a comparison by impregnation (NiFe/SiO 2 −IM) and deposition-precipitation (NiFe/SiO 2 −DP) methods, respectively. It was found that Ni−Fe alloy, the active sites for the hydrogenolysis of C−O bond, can be obtained by the reduction of NiFe 2 O 4 (IM) or phyllosilicate (DP and AE) by H 2 . The AE strategy can generate more phyllosilicate structure, which improves the dispersion of both Ni−Fe alloy and metallic Ni sites and allows the formation of more interface between these two kinds of sites as well. Therefore, the NiFe/SiO 2 −AE exhibits a significantly high catalytic performance in the HDO of phenol to cyclohexane. Moreover, the turnover frequency of Ni−Fe alloy sites over NiFe/SiO 2 −AE catalysts is much higher than those of other two catalysts. It is suggested that the enhanced synergy between the two kinds of active sites in the adsorption of C−O groups and hydrogen molecules ensures the superior intrinsic activity in HDO process.