Carbon monoxide (CO) generally produced and released from industrial, transportation and domestic activities. It causes potential harmful effects on the environment and the public health, hence complete elimination or abatement below the permissible levels is necessary. The present investigation describes the preparation of doped and supported manganese oxide catalysts. The doped manganese oxides were prepared by co-precipitation method and supported catalysts were prepared by wet impregnation method. Various instrumental techniques have been used to study these prepared compounds. XRD shows characteristic patterns for MnO2 and Mn2O3 samples, SEM and TEM images show that the particles are nano-sized. Thermal analysis give significant evidence for phase change of manganese oxides. Electrical resistivity that samples are semiconducting. These compounds are paramagnetic in nature. All these catalysts were tested for carbon monoxide oxidation reaction. Pd, Ag and Rh doped MnO2 catalysts showed higher CO conversion and even showed room temperature conversion. Supported catalysts also showed conversion at much lower temperature. Compare to doped MnO2 catalysts, the doped Mn2O3 catalysts gave conversion at higher temperature. Time on stream studies indicates that these catalysts are stable for longer period of time for CO oxidation reaction without any deactivation process. Higher oxygen in feed gas does not affect the CO oxidation activity of the catalysts, however it showed good activity. From time on stream experiments for moisture study, it is clear that the catalysts are highly stable for CO oxidation in presence of moisture in feed gas. Some of the catalysts showed higher activity for CO conversion in presence of moisture, indicating that moisture facilitates CO oxidation reaction over the catalyst surface.
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