焙烧温度对稀土钴系复合氧化物催化剂结构与性能的影响

Effects of Calcination Temperature on Structure and Catalytic Activity of Cobalt-Containing Rare-earth Oxide Catalysts

采用 X光衍射 (XRD)、程序升温还原 (TPR)、程序升温脱附 (TPD)、付立叶红外光谱 (FT- IR)、二甲苯完全氧化活性测定等方法 ,对 3种焙烧温度下所制备的稀土钴系复合氧化物催化剂进行了结构和性能表征 .结果表明 ,随着焙烧温度的升高 ,钙钛矿型 L a Co O3晶体逐渐发育完善 ,H2 - TPR谱的高温还原峰面积和峰温逐渐上升 ,而低温还原峰面积和峰温逐渐减少 .与此同时 ,O2 - TPD谱中 6 0 0℃附近的高温脱附峰逐渐增大 ,6 0 0℃以下低温脱附峰逐渐降低 。

The structure and properties of cobalt\|containing rare\|earth oxide catalysts at various calcination temperatures (450~850 ℃)have been studied using X\|ray diffraction(XRD), infrared spectroscopy(IR),temperature programmed reduction (TPR), temperature programmed desorption (TPD), measurements of conductivity and activity of xylene oxidation. It is shown that, as the calcination temperature increases, perovskite LaCoO\-3 gradually grows to perfection, the area of reduction peak and peak temperature in high temperature range in H\-2\|TPR profiles gradually increase, and those in low temperature range decrease. At the same time, the peak area near 600 ℃ in O\-2\|TPD enhances while that below 600 ℃ decreases. The catalytic activity of xylene complete oxidation and conductivity of catalyst increase with the increase of temperature in La\|Co\|O system.