Ni-H_3PW_(12)O_(40)/ZrO_2和Ni-Pt-H_3PW_(12)O_(40)/ZrO_2双功能催化剂的正戊烷异构化性能

用分步浸渍法制备了ZrO2负载的Ni-H3PW12O40(TPA)和Ni-Pt-TPA金属-酸性位双功能催化剂,用X射线衍射和傅里叶变换红外光谱对其进行了表征。以正戊烷为模型化合物,在常压临氢条件下考察了催化剂的异构化性能及还原温度和反应温度的影响。实验结果表明,Ni/ZrO2催化剂主要表现出氢解活性,产物为甲烷;向Ni/ZrO2中加入TPA后,Ni-TPA/ZrO2催化剂具有异构化作用,且随TPA含量的增加异构化能力逐渐增强,当Ni-TPA/ZrO2中Ni和TPA的质量分数分别为8%和30%时,催化剂的异构化效果较佳;向Ni-TPA/ZrO2中加入质量分数0.5%的Pt时,Ni-Pt-TPA/ZrO2催化剂的活性和选择性显著增加。

Isomerization of n-Pentane over Ni-H3PW12O40/ZrO2 and Ni-Pt-H3PW12O40/ZrO2 Bifunctional Catalysts

Two kinds of ZrO2 supported Ni-H3PW12O40(TPA) and Ni-Pt-TPA metal-acid bifunctional catalysts were prepared by conventional stepwise impregnations and were characterized by means of XRD and FTIR. n-Pentane was selected as model compound and was isomerized in hydrogen atmosphere to evaluate activities of the catalysts. The effects of reduction temperature and reaction temperature on activities of the catalysts were also investigated. Ni/ZrO2 shows strong hydrogenolysis activity to n-pentane and its isomerization activity appears only after addition of TPA to the catalyst. The catalytic isomerization activity is promising when the loading mass fraction of Ni and TPA are 8% and 30% (mass fraction) in Ni-TPA/ZrO2,respectively. Adding 0.5% (mass fraction) of Pt to Ni-TPA/ZrO2 catalyst,both conversion of n-pentane and selectivity to desired product increase evidently.