在水/环己烷微乳体系中制备高比表面积氧化锆

Synthesis of High Surface Area Zirconia in Water/Cyclohexane Microemulsion

在水 /TritonX 10 0 /环己烷 /正己醇微乳体系中合成了氧化锆粉末 ,经过 45 0℃氧气中焙烧和 40 0℃抽真空处理后 ,获得了比表面积高达 46 4m2 /g的氧化锆粉末 .X射线衍射测试表明 ,该化合物最初为无定形氧化锆 ,经 45 0℃焙烧 3h后开始出现四方晶相和少量的单斜晶相氧化锆 ,随着焙烧温度升高至 90 0℃ ,单斜晶相增加 ,但四方晶相仍是主要的 .在 6 0 0℃以下 ,添加氧化锰会阻止单斜晶相氧化锆的出现 ,使所制备的 15 %MnO2 ZrO2 具有较高的可逆吸附氮氧化物的能力 .

The high surface area zirconia powder was prepared in the water/Triton X-100/n-hexanol/cyclohexane water-in-oil microemulsion. The N-2 adsorption experiments showed that the BET surface area of the ZrO2 sample reached 464 m(2)/g after the sample was calcined at 450 V in oxygen and subsequently heated at 400 degreesC in vacuum. The XRD results revealed that the as-synthesized zirconia was amorphous, and after calcination at 450 V for 3 h, a mixture of tetragonal zirconia and a minor amount of monoclinic zirconia appeared. Upon further heating the sample at 900 V, the tetragonal zirconia phase still remained predominant although more monoclinic zirconia was observed. The addition of MnOx could prevent the formation of the monoclinic zirconia phase below 600 degreesC. The 15 % MnO2-ZrO2 sample with a specific surface area of 241 m(2)/g prepared in the water-in-oil microemulsion showed a large adsorption amount of nitric oxides and would possibly be used for reversible adsorption of nitric oxides.