摘要
加入硫酸根离子的ＴｉＯ２、Ｆｅ２Ｏ３和ＺｒＯ２等金属氧化物可以制成一种新型催化剂－－固体超强酸。而ＣａＯ、ＭｇＯ、ＺｎＯ和Ｌａ２Ｏ３等氧化物用同样的方法却不能被制成超强酸。硫酸铵附载的不能生成超强酸的氧化物没有硫酸铵在其表面上的分散，因此也没有发生ＳＯ２－４与这些氧化物表面的相互作用。这些氧化物与能生成超强酸的氧化物具有完全不同的表面性质。正是由于这种特异性使得它们不能被制成超强酸。
By addition of sulfate ion,TiO 2,Fe 2O 3 and ZrO 2 can be made into superacids.But,MgO,CaO,ZnO and La 2O 3,cannot be though treated in the same way as for TiO 2,Fe 2O 3 and ZrO 2.A rough mode was proposed that in the process of the thermal treatment of the TiO 2,Fe 2O 3 and ZrO 2 doped with ammonium sulfate the dispersion of ammonium sulfate onto the surface of the oxides might have happened,when the temperature is below ca.573K.It was inferred that the dispersion of ammonium sulfate is accompanied by interaction of sulfate ion in a coordinstion manner with the surface of the oxides in the same range of the temperature.As a result of the coordition a sort of surface sulfato complexs may be formed.The remaining complex molecules at higher temperature are associated with the development of the superacidity. So for contrast we have made some XPS and IR observations on CaO,MgO etc.doped with ammonium sulfate.All these oxides have similar XPS and IR behavier entirely different from that of the TiO 2,Fe 2O 3 and ZrO 2 doped with ammonium sulfate.SO it is proposed that for the CaO,MgO……doped with ammonium sulfate perhaps no dispersion of ammonium sulfate on and its coordination to the surface of the oxides incapable has happened owing to the different properties of theirs than the oxides capable.The speciality of this kind may be the cause for the CaO MgO……Cannot be made into the superacids.The dispersion of ammonium sulfate on and its interaction with the TiO 2,Fe 2O 3 and ZrO 2 might be a necessary part of the series of the steps happening on the surface of the TiO 2,Fe 2O 3 and ZrO 2 and leading to the subsequent production of superacidity of the TiO 2,Fe 2O 3 and ZrO 2 promoted by sulfate ion.
基金
国家自然科学基金
