【摘要】 用溶胶-凝胶法制备了不同组成的Mg-Co和Mg-Mn-Co复合氧化物,用于催化分解N₂O。在较高活性的Mg-Mn-Co表面浸渍K₂CO₃溶液,制备K改性催化剂。用X射线衍射（XRD）、N₂物理吸附（BET）、扫描电镜（SEM）、H₂程序升温还原（H₂-TPR）、O₂程序升温脱附（O₂-TPD）等技术表征催化剂结构,考察了复合氧化物的组成、K负载量等制备参数对催化剂活性的影响。结果表明,加入助剂K显著提高了催化剂活性,其中,0.02 K/MgMn_0.2Co_1.8O₄活性较高,有氧无水、有氧有水气氛400℃连续反应50 h,N₂O转化率分别保持97%和60%。有水-无水气氛交替实验表明,有水反应后再进行无水实验,K改性催化剂的稳定性较好。更多还原

【Abstract】 Mg-Co and Mg-Mn-Co composite oxides with different compositions were prepared by sol-gel method for N₂O catalytic decomposition in the presence of oxygen. Of Mg-Mn-Co catalysts,the one with higher activity was impregnated by K2CO₃ solution to make K-modified catalyst. These catalysts were characterized by X-ray diffraction（ XRD）,nitrogen physisorption（ BET）,scanning electron microscopy（ SEM）,temperatureprogrammed reduction of hydrogen（ H₂-TPR）,and temperature-programmed desorption of oxygen（ O₂-TPD）.The effect of preparation parameters such as compositions and potassium loadings on their catalytic activity has been investigated. The results show that K-modified catalysts exhibit better activity and higher resistance tow ards water in contrast to un-modified catalyst due to the weakness of surface metal-oxygen bonds. Among these catalysts,0.02 K/Mg Mn_0.2Co_1.8O₄ is the most active,over which 97% and 60% conversions of N₂O can be reached at 400 ℃ after continuous running for 50 h under the atmosphere of oxygen-alone and oxygen-steam together,respectively. When the steam is sw itched off,the catalytic activity of 0.02 K/MgMn_0.2Co_1.8O₄ can be restored to large extent,indicating the good water-resistance of K-modified catalyst.更多还原