CAJ | 학술논문

In order to investigate the influence of MnO2 modification methods on the catalytic performance of CuO/CeO2 catalyst for NO reduction by CO, two series of catalysts (xCuyMn/Ce and xCu/yMn/Ce) were prepared by co-impregnation and step-wise-impregnation methods, and characterized by means of X-ray diffraction (XRD), Raman spectra, H2-temperature programmed reduction (H2-TPR), in situ diffuse reflectance infrared Fourier transform spectra (in situ DRIFTS) techniques. Furthermore, the cata-lytic performances of these catalysts were evaluated by NO+CO model reaction. The obtained results indicated that:(1) The catalysts acquired by co-impregnation method exhibited stronger interaction owing to the more sufficient contact among each component of the catalysts compared with the catalysts obtained by stepwise-impregnation method, which was beneficial to the improvement of the reduction behavior;(2) The excellent reduction behavior was conducive to the formation of low valence state copper species (Cu+/Cu0) and more oxygen vacancies (especially the surface synergetic oxygen vacancies (SSOV, Cu+-Mn(4-x)+)) during the reaction process, which were beneficial to the adsorption of CO species and the dissociation of NO species, respectively, and further promoted the en-hancement of the catalytic performance. Finally, in order to further understand the difference between the catalytic performances of these catalysts prepared by co-impregnation and stepwise-impregnation methods, a possible reaction mechanism (schematic diagram) was tentatively proposed.