TiO2-Al2O3作为Mo催化剂担体的研究

Tio。－AI。oa二元氧化物的制备at艺大体可分为两种．一种是利用液相浸渍或气相沉积方法将Tio。担载在AI。0。上，使Tio。主要覆盖在AI。0。表面上［‘－1另一种是通过Ti盐和AI盐混合溶液共沉淀方法使Tio。和AI。0。均匀混合在一起【‘－’1．不同的制备工艺对Tio。－AI。03的表面结构和表面性质有很大影响问．我们曾报导用TICly蒸气化学气相沉积方法制备出了D02在1川2O3表面呈现十分均匀分布的DoZ一周。03复合氧化物担体＊’1．本文进一步考察D0。在周。0。表面的沉积对川。0。孔结构的影响，以及Ti02－A1203作为加氢精制MO催…

Studies of Titania-Alumina as Support for Molybdenum Catalysts

TiO2-Al2O3 binary okides were prepared by gas-phase deposition of TiCly on r-Al2os support. It was found that TiO2 deposition is formd by the reaction of TiCl4 vapour with OH- group on A12O3 stirface. The TiO2 loading increases with the number of gas phase deposition operations and the tetrahedral sites of Al2O3 surface was first covered by TiO2. S1ightly decrease of surface area) pore value and average of pore diameter of TiOz-AlzO3 compared with Al2O3 was observed. In Mo/TiO2-Al2O3 catalysts Mo ealsts maally in the form of octalledla and polymer Mo7O2' species, while no tetrahedral Mo species has been observed. The model of Mo/TiO2-Al2O3 catalyst could be imagined as a sandwich of MoO2-TiO2-Al2O3. Due to the weaker interaction between Mo species and A1zoa support in this case more Mo6+ ions in Mo/TiO2-Al2O3 sample are reduced to low valence state comparing with that of Mo/Al2O3 at 5o(f C in H2. The experimental results demonstrate that the HDS and HYD activities of Mo/TiO2-Al2O3 catalysts increase with Tioz content. It means that the full coverage of Al2o3 surface by TiO2 can driprove effectively the catalyst activity of molybdenum catalyst in hydrotreating process.