Low-temperature NO oxidation over Mn/TiO2 nanocomposite synthesized by chemical vapor condensation: Effects of Mn precursor on the surface Mn species

Mn/TiO2 nanocomposite materials for low-temperature selective NO oxidation was prepared through the impregnation of manganese acetate or manganese nitrate precursors on TiO2 particles fabricated by chemical vapor condensation. Improved low-temperature NO conversion resulted when manganese acetate precursor was used: NO oxidation activity was maximized at 88% at 225 °C. The materials were characterized by BET, XRD, HR-TEM, XPS and H2-TPR. The increased activity was attributed to the manganese acetate precursor providing well-dispersed Mn species on the material’s surface and increasing its surface area. Abundant Mn3+ species, hydroxyl groups, increased oxygen linking to Mn, and high concentrations of amorphous Mn on the surface resulted in the material’s improved activity towards NO oxidation at lower temperatures.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► MnOx/TiO2 materials synthesized by impregnation through chemical vapor condensation. ► Mn/Ti-CVC materials have large surface areas and a good dispersed. ► Mn3+ species and hydroxyl groups in Mn-MA/Ti-CVC were more abundance. ► Activity of the Mn-MA/Ti-CVC material improves the NO catalytic oxidation.