Speciality of the Surface of CaO,MgO etc. Doped with Ammonium Sulfate

By addition of sulfate ion,TiO₂,Fe₂O₃ and ZrO₂ can be made into superacids.But,MgO,CaO,ZnO and La₂O₃,cannot be though treated in the same way as for TiO₂,Fe₂O₃ and ZrO₂.A rough mode was proposed that in the process of the thermal treatment of the TiO₂,Fe₂O₃ and ZrO₂ 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 TiO₂,Fe₂O₃ and ZrO₂ 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 TiO₂,Fe₂O₃ and ZrO₂ might be a necessary part of the series of the steps happening on the surface of the TiO₂,Fe₂O₃ and ZrO₂ and leading to the subsequent production of superacidity of the TiO₂,Fe₂O₃ and ZrO₂ promoted by sulfate ion.