用EXAFS方法研究双功能催化剂NiO-MoO_3/γ-A_2O_3的表面分散

NiO-MoO_3/γ-Al_2O_3是加氢脱硫催化剂,关于此催化剂的制备、性能和结构已作了各方面的研究,发现不同制备方法对催化剂的性能有很大影响.我们已用EXAFS方法研究了NiO在γ-Al_2O_3表面上的分散,在此基础上我们继续用EXAFS方法研究不同制备条件下NiO和MoO_3在此催化剂表面上的分散,对此催化剂的结构作进一步的研究。     

用EXAFS研究NiO在γ-Al2O3表面上的分散

本文使用EXAFS方法研究NiO在γ-Al_2O_3的表面上的分散情况。文章讨论了Ni含量为7%、13%、18%、26%、35%的NiO/γ-Al_2O_3体系的径向结构函数图以及Ni含量为13%、26%的NiO/α-Al_2O_3样品的径向结构函数图,认为NiO能在γ-Al_2O_3表面上成单层分散。分散后的Ni-O距离接近NiO晶体的Ni-O距离,表明Ni离子和γ-Al_2O_3表面上的氧有很强的相互作用。     

用EXAFS研究NiO在γ-Al_2O_3表面上的分散

本文使用EXAFS方法研究NiO在γ-Al_2O_3的表面上的分散情况。文章讨论了Ni含量为7%、13%、18%、26%、35%的NiO/γ-Al_2O_3体系的径向结构函数图以及Ni含量为13%、26%的NiO/α-Al_2O_3样品的径向结构函数图,认为NiO能在γ-Al_2O_3表面上成单层分散。分散后的Ni-O距离接近NiO晶体的Ni-O距离,表明Ni离子和γ-Al_2O_3表面上的氧有很强的相互作用。     

用EXAFS方法研究双功能催化剂NiO-MoO3/γ-A2O3的表面分散那

The surface dispersion of bifunctional NiO-MoO_3/γ-alumina catalysts prepared by different procedures was studied with Ni-K EXAFS spectroscopy. The contents of NiO(13.6%) and MoO_3(16.5%) were the same in the three samples, which were a little higher than the monolayer dispersion capacity of each component on γ-Al_2O_3. The dispersion temperature was 450 ℃. The sample impregnated with NiO first shows that the NiO is monolayer-dispersed on γ-Al_2O_3 surface and the outer layer is MoO_3. The sample impregnated with MoO_3 and the outer layer is NiO. There is strong interaction between MoO_3 and γ-Al_2O_3 which affects the dispersion of NiO on the surface. The sample impregnated with NiO and MoO_3 simultaneously shows that the Ni is not dispersed in the form of NiO but another compound on the surface.