Abstract:

Al₂O₃-ZrO₂ composite oxides were prepared by coprecipitation and used as supports for Cu-based catalysts prepared by impregnation. The supports and the catalysts were characterized by X-ray diffraction（XRD），X-ray photoelectron spectroscopy（XPS），and scanning electron microscopy（SEM）. Effect of the composite oxides on the Cu-based catalysts for selective hydrogenation was studied using vapour phase hydrogenation of furfural to furfural alcohol as a probe reaction. Results showed that ZrO₂ can reduce the contact between CuO and Al₂O₃，and therefore，decrease the deep hydrogenation capacity of the Cu-based catalysts. Al₂O₃ can delay the crystallization of ZrO₂ and avoid Cu embedded into the ZrO₂ lattice which would lead to the decrease in catalystic activity. Cu/Al₂O₃-ZrO₂ catalyst made from Al₂O₃-ZrO₂ support with 20% ZrO₂ exhibited the highest activity for selective hydrogenation，which showed a higher low temperature activity and a higher high temperature selectivity in comparison with Cu/Al₂O₃ catalyst.