SO_4^(2-)Z/rO_2固体超强酸催化剂的结构表征

The structural characterization of SO_4^(2-)/ZrO_2 solid superacid catalyst

在不同H2SO4浓度和不同焙烧温度下制备的SO42-Z/rO2固体超强酸催化剂,用FT-IR和DSC等仪器对SO42-Z/rO2超强酸催化剂的表面酸性特征进行检测,然后对图谱进行分析,结合XRD仪器的检测结果,得出结论:在焙烧温度不太高时,催化剂表面除存在Lewis酸外,还有Brnōsted酸,B酸所占比例随焙烧温度的升高而增多。H2SO4的浓度、焙烧温度都是影响酸强度分布的重要因素,当H 2SO4浓度为1mol/L或焙烧温度为823K时,催化剂表面强酸中心最多。SO42-在无定形ZrO2、四方相ZrO2、单斜相ZrO2上的稳定性依次减小。

SO4^2 -/ZrO2 solid superacid catalyst is prepared in the different concentration and different calcination temperature.The surface acidity of SO4^2-/ZrO2 superacid catalyst was determined employing FT-IR and DSC, and the result of XRD to have attained following information. When calcination temperature is not very high, there are not only lewis acidic sites but also Bronsted acidic sites on the surface of catalysts.With the calcinations temperature getting high,the Bronsted acidic sites surface of catalysts.With the calcinations temperature getting high, the Bronsted acidic sites increase. Both H2SO4 concentration and calcinations temperature are important influence factors for the acidity distribution of catalyst.When H2SO4 is 1mol/L or calcination temperature is 823K, the stronger acidic sites are most. The stability of active sites on ZrO2 is following order ： amorphous ZrO2〉tetragonal ZrO2〉monoclinic ZrO2.