Study On The Preparation, Characterization Of ZrO₂ Composite Support And The Property Of Ni-based Catalyst

ZrO₂ is a catalyst support with good chemical stability, oxidation-reduction properties and acidity-alkalescence on its surface, but it has small specific surface area and is prone to agglomerate. This dissertation takes the route of the following processes: for the sake of increasing the specific surface area, nanosized ZrO₂ was loaded on different basic support to prepare supported nanosized composite supports. The composite supports can take the advantage of nanosized ZrO₂ and the higher specific surface, good pore size distribution and good thermal stability of basic support at the same time. In the dissertation, the CH₄-CO₂ reforming reaction of Ni-based catalysts was studied and the prepared samples were characterized by XRD, FT-IR, nitrogen adsorption experiments, TPR and CO(CO₂,Pyridine)-TPD.Compared to non-supported ZrO₂-AhO₃ composite support, the dispersion of ZrO₂ and specific surface area of supported ZrO₂-c/Al₂O₃-c composite support were larger. Adding the oxide of MgO (Nd₂O₃ or TiO₂) to ZrO₂-Al₂O₃, ZrO₂ crystal phase and the specific surface area of ZrO₂-Al₂O₃ composite supports were changed, in which the effect of TiO₂ was the best for the specific surface area increased, the t-ZrO₂ granularity decreased and new compounds between TiO₂ and ZrO₂ formed. The activity sequence of Ni-based catalysts was consistent to that of the reductive peak areas of TPR and active surface areas, reverse to that of NiO granularity. The activity of Ni/ZrO₂-c/Al₂O₃-c was not only higher than that of Ni/ZrO₂-Al₂O₃, but also higher than that of Ni/ZrO₂-TiO₂-Al₂O₃.Diffraction peak of ZrO₂ was not found in the XRD profiles of supported ZrO₂-c/Al₂O₃-c and ZrO₂-c/Al₂O₃-SiO₂-c composite support, which indicated that ZrO₂ was dispersed highly to Al₂O₃-c and Al₂O₃-SiO₂-c. The specific surface area, the interaction between NiO and ZrO₂, the dispersion degree, the active center and the ability of adsorption CO₂ of ZrO₂-c/Al₂O₃-c and ZrO₂-c/Al₂O₃-SiO₂-c were improved by supporting ZrO₂-c to Al₂O₃-c and Al₂O₃-SiO₂-c, in which the effect of ZrO₂-c/Al₂O₃-c was better. The activy of Ni/ZrO₂-c/Al₂O₃-c catalyst was higher...