溶胶-凝胶法制备Ni_xCo_(1-x)CoAlO_4尖晶石型复合氧化物及其催化分解N_2O性能(英文)

Catalytic decomposition of N_2O over Ni_xCo_(1-x)CoAlO_4 spinel oxides prepared by sol-gel method

用溶胶凝胶法制备了一组NixCo1-xCoAlO4尖晶石型复合氧化物,并采用表面润湿浸渍K2CO3溶液进行了K掺杂改性,用于有氧气氛下的N2O催化分解反应。采用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)等技术对催化剂进行了表征,考察了催化剂组成、母液pH值、K负载量等制备参数对其催化活性的影响。结果表明,母液pH值为3、K/(Ni+Co)物质的量比为0.1的K/Ni0.15Co0.85CoAlO4催化剂具有较高的N2O分解活性,450℃N2O可完全分解。助剂K的加入弱化了催化剂表面金属氧键,提高了催化剂的还原性、催化活性和抗水性。

NixCo1-xCoAlO4 spinel oxides with different compositions were prepared by sol-gel method and further modified with K2CO3 by incipient impregnation. The NixCo1-xCoAlO4 spinel oxides were characterized by means of nitrogen physisorption,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and temperature-programmed reduction by hydrogen（H2-TPR）; the effect of preparation parameters such as composition,mother liquid pH value,and potassium loading on their catalytic activity in N2O decomposition was investigated. The results show that the K / Ni0. 15Co0. 85 CoAlO4 catalyst prepared with a pH value of 3 and a K/（Ni ＋ Co） molar ratio of 0. 1 is most active for N2O decomposition; over it,N2O can be completely decomposed into nitrogen and oxygen at 450 ℃ in the presence of oxygen. K-modified catalysts exhibit high catalytic activity,good reducibility and resistance towards water,as K species may be able to weaken the surface metal-oxygen bonds.