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.

摘要：

采用共沉淀法制备Al₂O₃-ZrO₂复合氧化物，并以此为载体制备负载型Cu基催化剂，运用X射线衍射、X射线能谱、扫描电子显微镜对载体和催化剂进行表征。以糠醛气相加氢制糠醇反应为探针，考察复合氧化物对Cu基催化剂选择加氢活性的影响。结果表明，Al₂O₃-ZrO₂复合氧化物中ZrO₂的存在会减少CuO与Al₂O₃的接触，降低Cu基催化剂的深加氢能力；Al₂O₃有助于延迟ZrO₂的晶化，避免活性组分Cu嵌入到ZrO₂晶格中导致催化活性下降。载体中ZrO₂质量分数为20%时，Cu/Al₂O₃-ZrO₂催化剂选择加氢活性最高，与Cu/Al₂O₃催化剂相比，该催化剂具有较好的低温加氢活性和高温加氢选择性。