Mn-doped Ceria Solid Solutions for CO Oxidation at Lower Temperatures

In this investigation, Mn-doped CeO2(CM) catalysts were prepared by co-precipitation (CP), sol-gel (SG), and hydrothermal (HT) methods and characterized by XRD, ICP-OES, N2 adsorption–desorption, SEM, TEM-HREM, Raman, XPS, FT-IR, XPS and H2-TPR techniques, and evaluated for CO oxidation activity. The CM catalyst obtained by HT method showed superior CO oxidation performance at much lower temperature (T50 = ~355 K). The better performance of CM-HT catalyst is ascribed to its larger surface area, higher concentration of surface adsorbed oxygen, enhanced reducibility, and more oxygen vacancy sites. Further, it was found that the CM-HT catalyst is fully recyclable for over four runs while maintaining its high activity, which suggests that it is a better catalyst for CO oxidation at lower temperatures.