Study On The Preparation, Characterization And Supports Of Au-Pd Bimetallic Catalysts For Thiophene Hydrodesulfurization

In this article, the Au-Pd bimetal catalysts are used in the thiophene hydrodesulfurization(HDS) reaction. The effects of calcination temperature, preparing methods and the sorts of the supports, reduce methods and transition metals (Ru, Ni and CoO) doped on HDS activity of Au-Pd/TiO₂-Al₂O₃ catalysts are studied. The prepared samples are characterized by XRD, ICP, TG-DTA, IR, nitrogen adsorption experiments, H₂-TPR and CO(Pyridine)-TPD.1. A serials of metal oxide and metal mixed oxide supports are prepared (Al₂O₃, TiO₂-Al₂O₃(1:1 mol) , ZrO₂-Al₂O₃(1:1mol) ,CeO₂-Al₂O₃(1:1 mol) , SiO₂-15wt%TiO₂, SiO₂-15wt%ZrO₂,SiO₂- 15wt%CeO₂, SiO₂- 15wt%Al₂O₃), and the catalysts are prepared by deposition-precipitation (DP) method. The results indicate that Au-Pd/TiO₂-Al₂O₃ catalyst has better hydrodesulfurization activity and stability than those of Au-Pd/Al₂O₃ catalyst. Compare with Au-Pd/Al₂O₃ catalyst, Au-Pd/TiO₂-Al₂O₃ catalyst has higher acid site density and acid strength, active surface area and absorbing amount of H₂ and CO.2. Mesoporous TiO₂-Al₂O₃ are prepared by sol-gel, coprecipitation(CP) and deposition-precipitation (DP) methods, respectively. The influence of preparing methods of supports on the performance of loaded Au-Pd bimetal catalyst for thiophene HDS reaction is studied. Results showe that TiO₂-Al₂O₃ supports prepared by sol-gel, CP and DP methods are all mesoporous materials, TiO₂-Al₂O₃ prepared in sol-gel method has larger surface area and pore volume. Au-Pd/TiO₂-Al₂O₃ catalysts has good HDS activities and the Au-Pd/TiO₂-Al₂O₃ (S) is the best. The HDS activities of thiophene correlate with the content of the Au_xPd_y alloy in the catalysts. Compare with Au-Pd/TiO₂-Al₂O₃ (C) and Au-Pd/TiO₂-Al₂O₃ (D) catalysts, the Au-Pd in the Au-Pd/TiO₂-Al₂O₃ (S) catalyst has stronger interaction with support, larger active surface area and better dispersion, more number of Au_xPd_y alloy and acid sites, and apparent activation energy was lower, all these are advantageous to catalyst active...