溶胶凝胶法制备CexCo2-xAlO4复合氧化物及其催化分解N2O

用柠檬酸-溶胶凝胶法制备了CexCo2-xAlO4系列复合氧化物和K2CO3改性催化剂，考察了复合氧化物组成、母液pH值、钾负载量对N2O催化剂活性的影响，用N2物理吸附、X射线衍射（XRD）、扫描电镜（SEM）、H2程序升温还原（H2-TPR）、O2程序升温脱附（O2-TPD）、X射线光电子能谱（XPS）等方法表征了催化剂结构。结果表明：用Ce取代Co2AlO4中部分Co制得的CexCo2-xAlO4复合氧化物催化活性有所提高，其中母液pH=2、组成为Ce0.05Co1.95AlO4的催化剂活性较高，该催化剂具有较高的比表面积、较小的晶粒及Ce-Co间的协同效应；进一步研究表明，由于K粒子的电子效应，使得0.05K/Ce0.05Co1.95AlO4的催化活性又优于其他催化剂，有氧气氛中450C连续反应50h，N2O分解率达98.5%。

Catalytic decomposition of N2O over CexCo2-xAlO4 composite oxides prepared by sol-gel method

A series of CexCo2-xAlO4 composite oxides were prepared by citric acid based sol-gel method and further modified by K2CO3. The effect of composite oxide compositions, pH values of mother liquid, and potassium loadings on catalytic activity for N2O decomposition was investigated. The bare and K-modified CexCo2-xAlO4 catalysts were characterized by means of nitrogen physisorption, X-ray diffraction(XRD), scanning electron microscopy(SEM), hydrogen temperature-programmed reduction(H2-TPR), temperature-programmed desorption of oxygen(O2-TPD), and X-ray photoelectron spectroscopy(XPS) techniques. The results show that the catalytic activity of CexCo2-xAlO4 composite oxides was enhanced in comparison with Co2AlO4, and the optimal composition was Ce0.05Co1.95AlO4 with larger surface area, smaller particle size and the Ce-Co synergistic effect. Further results indicate that 0.05K/Ce0.05Co1.95AlO4 catalyst due to the electronic effect of potassium on cobalt oxides was more active than other catalysts, over which N2O conversions reached 98.5% at 450C after 50h continuous reaction in the presence of oxygen.