Study On Supported Co,Ni Catalysts For Hydrodesulfurization Of Thiophene

In the first part of the thesis, Pt and Pd were selected as the second components to add Co-B/γ-Al₂O₃ to promote its activity for thiphene hydrodesulfurization. Co-M-B/γ-Al₂O₃ (M=Pt,Pd) catalysts were prepared by chemical reduction method. The influence of Pt,Pd on the properties of Co-B/γ-Al₂O₃ was investigated by differential thermal analysis (DTA), inductively coupled plasma(ICP), temperature programmed reduction (TPR), temperature programmed desorption of hydrogen (H₂-TPD). The results showed that the Co-Pt-B/γ-Al₂O₃ and Co-Pd-B/γ-Al₂O₃ catalysts exhibited better catalytic performance than Co-B/γ-Al₂O₃. The addition of Pt or Pd changed the composition Co-B alloy, resulting in the enhance of the thermal stability of the catalyst. Moreover, the reduction temperature of Co-B/γ-Al₂O₃ and the strength of H₂ adsorption over the surface of Co-B/γ-Al₂O₃ were both decreased by the addition of Pt or Pd, but the active surface area and the number of the adsorption sites were increased, which are in favor of the reaction.In the second part of the thesis, Ni/ZnO catalyst was prepared by impregnation method for HDS of thiophene, comparing to the Ni/Al₂O₃ catalyst. ZnO was prepared by combustion synthesis method and the effect of Nd on Ni/ZnO catalyst was studied The results showed that: (â…°) Ni/ZnO catalyst was better than Ni/Al₂O₃ catalyst for HDS of thiophene. The reasons for it were that the more amount of adsorption centers and the stronger interaction between ZnO and Ni exisited over the surface of Ni/ZnO than those over Ni/Al₂O₃, and ZnO had promoting effect on catalysis. (â…±) Ni-Nd/ZnO exhibited higher catalytic activity than Ni/ZnO. The active surface area, the number of the adsorption sites and the acid property of Ni/ZnO were increased by the addition of Nd, which are in favor of the reaction. (â…²) Ni/ZnO(C) exhibited higher catalytic activity than Ni/ZnO, which was due to the bigger specific surface area and average pore diameter in ZnO(C). Compared with Ni/ZnO, Ni/ZnO(C) show bigger active surface area, the more H₂ adsorbing center, the weaker H₂ absorbing strength, and stronger acid property, also resulting in the higher activity.