Catalytic decomposition of N2O over NixCo1–xCoAlO4 spinel oxides prepared by sol-gel method

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/Ni0.15Co0.85CoAlO4 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°C 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.