Low temperature CO oxidation over nano-sized Cu-Pd doped MnO2 catalysts

Abstract

Cu-Pd doped manganese dioxide catalysts were prepared by the dextrose assisted co-precipitation method. All the catalysts prepared were tested for CO oxidation activity. The Cu-Pd doped MnO2 catalysts showed much enhanced activity towards CO oxidation at low temperature, whereas pristine MnO2 showed conversion at higher temperature. Cu-Pd doped MnO2 catalysts even showed room temperature conversion. Catalysts show higher activity for CO conversion in the presence of moisture, indicating that moisture facilitates CO oxidation. Stability studies showed that catalysts are stable for long periods of time in the presence as well as in the absence of moisture. XRD authenticates the formation of a nanocrystalline MnO2 phase. The SEM images confirm the formation of nanosize particles and show spherical morphology. From the TEM images, it is clear that particles show spherically elongated morphology. Thermal analysis data give significant evidence of phase change of MnO2 with increasing temperature. XPS data showed that Mn is present in 4+ oxidation state in MnO2.