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SO2 -4/ZrO2 的超强酸酸性与硫酸根含量、氧化锆状态和制备过程有关。在较低温度下ZrO2 由无定形转变成四方晶相 ,在较高温度下由四方晶相转变成单斜晶相。SO2 -4对上述的相变有阻抑作用。对于引入稀土的样品 (Zr/RE摩尔比为 6 0～ 2 4 0 ) ,稀土对ZrO2 在较低温度下由无定形转变成四方晶相的相变无明显的影响 ,但对较高温度下由四方晶相向单斜晶相的相变有明显的阻抑作用 ,因此 ,增强了四方晶态相和酸性中心的热稳定性 ,同时催化剂的活性稳定性也有显著的提高。
The superacid acidity of SO2-4 / ZrO2 is related to the sulfate content, the state of zirconia and the preparation process. ZrO2 transforms from amorphous to tetragonal at lower temperatures and from tetragonal to monoclinic at higher temperatures. SO2 -4 has a suppressive effect on the above phase transition. For rare earth-doped samples (Zr / RE molar ratio of 60 ~ 240), rare earth ZrO2 phase transition from amorphous to tetragonal phase at lower temperature had no significant effect, but at higher temperature The phase transition from tetragonal phase to monoclinic phase is obviously inhibited. Therefore, the thermal stability of the tetragonal phase and the acidic center is enhanced, and the activity stability of the catalyst is significantly improved.