Preparation of Ce-MnO Composite Oxides via Coprecipitation and Their Catalytic Performance for CO Oxidation.

Ce-MnO composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60-140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation performance of CO was investigated using X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), H temperature programmed reduction (H-TPR), CO-temperature programmed desorption (CO-TPD), and in situ infrared spectra. The experimental results reveal that under the same test conditions, the CO conversion rate of pure MnO reaches 95.4% at 170 °C. Additionally, at 140 °C, the Ce-MnO series composite oxide catalyst converts CO at a rate of over 96%, outperforming single-phase MnO in terms of catalytic performance. With the decrement in Ce content, the performance of Ce-MnO series composite oxide catalysts first increase and then decrease. The Ce MnO catalyst behaves best when Ce:Mn = 1:1, with a CO conversion rate of 99.96% at 140 °C and 91.98% at 100 °C.