【摘要】 以不同来源的-αAl2O3为载体制备了用于催化CO偶联制草酸二甲酯反应的Pd/-αAl2O3催化剂,利用X射线衍射、N2吸附和X射线能谱等手段对载体进行了表征.结果表明,催化剂活性与载体的比表面积没有必然联系,但依赖于载体孔容及孔径的分布范围.同时-αAl2O3的纯度和杂质种类对催化剂活性也有影响,少量钠氧化物和-γAl2O3的存在会大大降低催化剂的活性.此外,利用CO化学吸附法分析了催化剂活性组分的分布情况.结果表明,催化剂表面活性金属Pd的分散度达到3.94%以上时,分散度的进一步增大对CO偶联反应没有明显影响.更多还原

【Abstract】 A series of Pd/α-Al₂O₃ catalysts for the CO coupling reaction were prepared with（α-Al₂O₃） from five different sources.The influence of impurities,specific surface area,and pore structure of the support on the catalyst activity was studied.（X-ray） diffraction and energy dispersive（X-ray） analysis results confirm the existence of various impurities in three（αAl₂O₃） samples due to their different production methods.The sodium oxides and（γ-Al₂O₃） in the support decrease the catalyst activity from 45%CO conversion to 10%.The N₂ adsorption result shows that the specific surface area and pore volume of the support are not as much important as the pore distribution for the activity of Pd/（α-Al₂O₃,） and the double pore structure of the support is necessary for preparing high activity catalysts. Moreover,the results of CO chemical adsorption on the five catalysts show that the CO coupling reaction does not need many active sites to get a high CO conversion.更多还原