Abstract:
In addition to the three conventional pollutants (CO, NO
x and HCs) of traditional gasoline vehicles, gasohol vehicle exhausts also contained alcohols and aldehydes which led to photochemical smog and ozone pollution. CuO
x, MnO
x and CuMnO
x catalysts were prepared by the co-precipitation method for catalytic combustion of low-concentration ethanol emitted from gasohol vehicles in cold start. Moreover, the catalysts were characterized by BET nitrogen adsorption-desorption, X-ray diffraction (XRD), hydrogen temperature programmed reduction (H
2-TPR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that CuMnO
x catalyst had a better low-temperature catalytic activity for low-concentration ethanol. When the reaction temperature was 185 °C, the yield of CO
2 was as high as 86%, better than that of single CuO
x catalyst (about 20%). Meanwhile, CuMnO
x had a higher CO
2 selectivity than MnO
x. The interactions between Cu and Mn altered the texture, structure and oxidation performance of the catalyst, resulting in the changes in the crystal morphology and electronic environment of the catalyst. There were a large number of oxygen defect sites on the surface of CuMnO
x, which was in favour of the adsorption of oxygen molecules, then turning into surface active oxygen species.