多孔猝冷Ni催化剂的热稳定性研究

Thermal Stability of Skeletal Rapidly Quenched Ni Catalyst

利用猝冷技术制备了Ni50Al50猝冷合金,用碱抽提Al的方法进行活化,制成Ni基猝冷合金催化剂.采用X射线衍射(XRD)、扫描电镜(SEM)、氮物理吸附和差示扫描量热(DSC)等表征手段研究其受热过程.同时,也对普通的RaneyNi催化剂进行同样的考察,研究两者之间的差别.研究发现:多孔猝冷催化剂中残留更多的Ni2Al3物相,它起着稳定催化剂骨架的作用,使得多孔猝冷催化剂的骨架具有更高的热稳定性;另一方面,由于猝冷催化剂中的Ni晶格发生畸变,晶粒更加容易受热长大.

Rapidly quenched Ni_(50)Al_(50) alloy was prepared by the single roller melt-spinning method and activated by alkaline leaching of Al, thus Ni-based skeletal alloy catalyst was obtained. A variety of experimental techniques, including powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption and differential scanning calorimetry (DSC) have been used to investigate its thermal stability. As compared to Raney Ni, the rapidly quenched catalyst has residual Ni_(2)Al_(3) phase which can stabilize the skeleton and inhibit the collapse of the pores. On the other hand, the crystallites in the rapidly quenched catalyst tend to agglomerate, attributable to the metastable nature of the rapidly quenched catalyst as manifested by its expanded lattice constant.