In this research, MnOx catalysts supported on Multi/Single-walled carbon nanotubes and activated carbons were prepared by incipient wetness impregnation method and their low-temperature selective catalytic properties were studied. H2-TPR, XRD, TEM and ASAP were employed to probe the effect of carbonaceous supports and the nature of the oxidation state of the manganese appeared on catalyst surface. Based on the obtained results, it was concluded that 12wt% MnOx over single-walled nanotube had the highest activity. H2-TPR analyze of the catalyst supported on single-walled nanotubes revealed the presence of partially undecomposed Mn-nitrate species and formation of MnO2/Mn2O3 phases over the surface of the support. However, H2-TPR analyze of the catalyst supported on active carbon proved the dominant phase of manganese oxide is Mn3O4. So, in this way, the oxidation state of manganese seemed to be the key factor to get the best activity in comparison with surface area and active phase dispersion.
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