Đặc trưng và hoạt tính xúc tác cho phản ứng oxi hóa CO của các oxit CuO, CeO2 và oxit hỗn hợp CuO-CeO2

Abstract

CuO-CeO₂ mixed oxide with 7.5 % CuO content prepared by co-precipitation method, has been tested for the oxidation of CO conditions at 30-327 ^oC. Catalysts have been characterized by means of X-ray diffraction (XRD), H₂- temperature-programmed reduction (H₂-TPR) and Raman spectroscopy. H₂-TPR results indicated that there are three CuO species in the mixed oxide: the Cu²⁺ mostly exists in the bulk CuO and the left in Cu_xCe_1-xO_2-dsolid solution and finely dispersed CuO species on the surface of CeO₂. The calculating results of the oxygen vacancy concentration in CuO-CeO₂ mixed oxide from Gaussian deconvolution of Raman spectra showed that, oxygen vacancy concentration in CuO-CeO₂ mixed oxide was 4.5 %. Investigated catalytic possibility of CuO, CeO₂ and CuO-CeO₂ mixed oxide in transformation of CO. The results showed that, CuO-CeO₂ mixed oxide has higher catalytic activity compared CuO and CeO₂ oxides. The synergistic interaction between CuO and CeO₂ is the main factor responsible for high catalytic activity of CuO-CeO₂ mixed oxide. At ambient temperature (30 ^oC), yield of CO treatment of CuO-CeO₂ mixed oxide was relatively high (53.2 %) and the transformation of CO almost finished at the temperature 207 ^oC (98.4 %).

Keywords: CuO-CeO₂, CO oxidation, co-precipitation, catalyst.