Ni/Al_2O_3-SiO_2催化剂表面性质及顺酐加氢性能

Study of surface properties of Ni /SiO_2-Al_2O_3 catalysts and their hydrogenation performance of maleic anhydride

以Al2O3质量分数为10%的Al2O3-SiO2复合氧化物为载体,通过浸渍法制备一系列不同Ni负载量的Ni/Al2O3-SiO2催化剂。运用BET、XRD、H2-TPR和NH3-TPD-MS方法研究催化剂表面性质随活性金属Ni负载量的变化规律,探讨催化剂表面性质的变化对其顺酐加氢活性、选择性及催化剂稳定性的影响。结果表明,Ni/Al2O3-SiO2催化剂中的Ni质量分数由5.0%增加至12.5%时,γ-丁内酯收率由7.9%快速增至38.9%,进一步增加Ni质量分数至20.0%,γ-丁内酯收率增加趋于平缓。催化剂中Ni活性物种与催化剂酸性中心的数量是影响催化剂顺酐加氢活性的主要原因。

Using Al2O3-SiO2 composite oxide with 10wt% Al2O3 as the support,a series of catalysts with different Ni loading was prepared by impregnation method.The surface properties of as-prepared catalysts were characterized by BET,XRD,H2-TPR and NH3-TPD-MS methods.The effects of the surface properties on the activity,selectivity and stability of the catalysts were investigated.The results showed that when the nickel content increased from 5.0wt% to 12.5wt%,γ-butyrolactone yield rapidly increased from 7.9% to 38.9%.Further increasing the nickel content to 20.0wt%,the yield of γ-butyrolactone increased slowly.The numbers of Ni active species and acid sites are the main reasons for affecting the catalytic activity of the catalysts for maleic anhydride hydrogenation.