Preparation, Characterization And Catalytic Application Of Mesoporous ZrO₂-Al₂O₃ Mixed Oxides

Development of hydrotreating catalysts with novel structure is a key issue to promote the hydrotreating process for heavy or residual oil with the request of friendly environment. Modifying the nature of supports is one of the methods for improving the catalyst. In this paper, the mesoporous ZrO₂-Al₂O₃ mixed oxides was synthesized and their catalytic applications were investigated. The synthesis conditions were systematically investigated to optimize the structure of ZrO₂-Al₂O₃ mixed oxide. The evaluation of catalytic property of this mixed oxide in hydrodesulfurization process and methanol reforming with CO₂ was carried out in micro reaction device.The ZrO₂-Al₂O₃ mixed oxides were prepared via double hydrolysis method and hydrothermal method. The results showed that the interaction between zirconium and aluminum result in the formation of a little solid solution. Lewis acid sites existed in the mixed oxides. The pore size distribution can be tuned by the pH value. The results also exhibited that ZrO₂-Al₂O₃ mixed oxides prepared by using (NH4)2CO3 as precipitator possesses bimodal pore size distribution, bear high surface area and large pore volume. The orthogonal experiment is good method for optimization of parameters and finding the optimum condition.The catalysts Ni/ZrO₂-Al₂O₃ for CH4-CO₂ reforming reaction were evaluated. The results showed that the activity of Ni/ZrO₂-Al₂O₃ was a little lower than Ni/Al₂O₃, but its ability of resistance to carbon deposition was better than Ni/Al₂O₃. The catalysts CoMo/ZrO₂-Al₂O₃ for hydrodesulfurization reaction were evaluated. The results showed that the catalysts CoMo/ZrO₂-Al₂O₃ bear large pore size were more active than CoMo/Al₂O₃, the existence of ZrO₂ can improve the hydrogenation ability of the catalysts.