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

Abstract

AbstractA phyllosilicate‐derived NiFe/SiO2 catalyst (NiFe/SiO2−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/SiO2−IM) and deposition‐precipitation (NiFe/SiO2−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 NiFe2O4 (IM) or phyllosilicate (DP and AE) by H2. 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/SiO2−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/SiO2−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.