N_2O在Mg-Co和Mg-Mn-Co复合氧化物上的催化分解  

Catalytic decomposition of N_2O over Mg-Co and Mg-Mn-Co composite oxides

作　　者：郑丽[1] 吴藏藏 徐秀峰[1] 

机构地区：[1]烟台大学化学化工学院,山东烟台264005

出　　处：《燃料化学学报》2016年第12期1494-1501,共8页Journal of Fuel Chemistry and Technology

基　　金：山东省重点研发计划(2016GSF117003);烟台大学研究生科技创新基金(GIFYTU)资助~~

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N_2O。在较高活性的Mg-Mn-Co表面浸渍K_2CO_3溶液,制备K改性催化剂。用X射线衍射(XRD)、N_2物理吸附(BET)、扫描电镜(SEM)、H_2程序升温还原(H_2-TPR)、O_2程序升温脱附(O_2-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_(0.2)Co_(1.8)O_4活性较高,有氧无水、有氧有水气氛400℃连续反应50 h,N_2O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。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 K2CO3solution to make K-modified catalyst. These catalysts were characterized by X-ray diffraction (XRD), nitrogen physisorption (BET), scanning electron microscopy (SEM), temperature-programmed 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 towards water in contrast to un-modified catalyst due to the weakness of surface metal-oxygen bonds. Among these catalysts, 0.02 K/MgMn0.2Co1.8O4is 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 switched off, the catalytic activity of 0.02 K/MgMn0.2Co1.8O4can be restored to large extent, indicating the good water-resistance of K-modified catalyst. © 2016, Science Press. All right reserved.

关 键 词：N2O催化分解 Mg-Co复合氧化物 Mg-Mn-Co复合氧化物 K改性催化剂 催化性能 

分 类 号：O643.3[理学—物理化学]