γ-Al_2O_3负载钴铜复合氧化物的制备及其催化分解N_2O性能

Preparation of γ-Al_2O_3 supported composite Co-Cu oxides and their performances in catalytic decomposition of N_2O

采用等体积浸渍法制备γ-Al_2O_3负载钴铜复合氧化物催化剂(Co9Cux/γ-Al_2O_3),利用XRD,BET,H_2-TPR等手段对催化剂进行表征。考察了Cu负载量、有无O_2存在等对催化剂活性的影响,研究了催化剂的催化机理及其稳定性。表征结果显示,Co_9Cu_x/γ-Al_2O_3催化剂具有尖晶石结构,随Cu负载量的增加,催化剂的比表面积下降,CuO还原峰向低温区移动,Cu的负载量达15%(w)时,继续增加Cu负载量,催化剂比表面积基本保持不变,钴系氧化物的存在提高了催化剂活性。实验结果表明,Co9Cu15/γ-Al_2O_3催化剂的活性最高,N2O转化率在565℃时达100%;Co9Cu15/γ-Al_2O_3催化剂具有良好的稳定性,在有O_2条件下,560℃连续催化分解N_2O反应24 h,N_2O转化率仍大于97%。

Co9Cux/γ-Al_2O_3 catalysts were prepared through impregnation and characterized by means of XRD,BET and H2-TPR. The effects of active component loadings and O2 atmosphere on the N2 O decomposition over the catalysts were investigated. The mechanism of the catalytic decomposition and the stability of the catalysts were discussed. The experimental results exhibited the spinel structure of the Co9Cux/γ-Al_2O_3 catalysts. With increasing Cu loading,the specific surface area of the catalysts decreased and the reduction peaks shifted to low temperature area. The specific surface area of the catalysts did not change with increasing Cu loading when the Cu content was more than 15%（w）. The doping of cobalt oxide could promote the activity of the catalysts. The experiment results revealed that the activity of Co9Cu15/γ-Al_2O_3 was the highest and the N2 O conversion reached 100% at 565 ℃. Under O2 atmosphere, the catalytic decomposition rate of N2 O was still more than 97% after the reaction at 560 ℃ for 24 h.