载体焙烧温度对Ni/SiO2-Al2O3催化剂稳定性的影响

为了获得高水热稳定的负载Ni催化剂，延长催化剂在含水液相体系中的使用寿命，以不同温度焙烧的SiO₂-Al₂O₃为载体，采用浸渍法制备Ni/SiO₂-Al₂O₃催化剂，通过吡啶-原位傅立叶变换红外光谱、X射线衍射、NH₃-程序升温脱附和H₂-程序升温还原等方法进行表征，以水相1,4-丁炔二醇加氢为探针反应，研究载体焙烧温度对Ni/SiO₂-Al₂O₃催化剂催化加氢性能及含水体系中稳定性的影响。结果表明,在(400~800) ℃，随着载体焙烧温度升高，活性组分Ni存在状态及催化剂加氢活性变化较小，但催化剂的水热稳定性下降，造成这一现象的原因是随着载体焙烧温度升高，载体表面SiO₂聚集，暴露的Al³⁺增加，载体水合程度增大。载体焙烧温度400 ℃时，Ni/SiO₂-Al₂O₃催化剂表现出最佳的水热稳定性。

Influence of support calcination temperatures on stability of Ni/SiO2-Al2 O3 catalysts

Using SiO2-Al2O3 calcined at different temperatures as the supports,Ni / SiO2-Al2O3 catalysts were prepared by the impregnation method in order to obtain the supported Ni catalysts with high hydrothermal stability and prolong the service life of the catalysts in the aqueous phase system. The catalysts were characterized by Py-FTIR,XRD,NH3-TPD and H2-TPR. The effects of the support calcination temperatures on the catalytic performance of Ni / SiO2-Al2O3 catalysts were studied by using the hydrogenation of aqueous phase 1,4-butynediol as a probe reaction. The results showed that in the range of（ 400-800） ℃,the support calcination temperatures had little effect on the state of active component Ni and the hydrogenation activity of the catalysts. With the increase of support calcination temperature,however,the hydrothermal stability of the catalysts decreased due to SiO2 gathering on the support surface,the increase of exposed Al3 ＋and the hydration degree enhancement of the support. When the calcination temperature was 400 ℃,Ni / Si O2-Al2O3 catalyst exhibited the best hydrothermal stability.