Reverse Micelle Strategy for the Synthesis of MnO(x)–TiO(2) Active Catalysts for NH(3)-Selective Catalytic Reduction of NO(x) at Both Low Temperature and Low Mn Content

[Image: see text] MnO(x)–TiO(2) catalysts (0, 1, 5, and 10 wt % Mn nominal content) for NH(3)-SCR (selective catalytic reduction) of NO(x) have been synthesized by the reverse micelle-assisted sol–gel procedure, with the aim of improving the dispersion of the active phase, usually poor when obtained by other synthesis methods (e.g., impregnation) and thereby lowering its amount. For comparison, a sample at nominal 10 wt % Mn was obtained by impregnation of the (undoped) TiO(2) sample. The catalysts were characterized by using an integrated multitechnique approach, encompassing X-ray diffraction followed by Rietveld refinement, micro-Raman spectroscopy, N(2) isotherm measurement at −196 °C, energy-dispersive X-ray analysis, diffuse reflectance UV–vis spectroscopy, temperature-programmed reduction technique, and X-ray photoelectron spectroscopy. The obtained results prove that the reverse micelle sol–gel approach allowed for enhancing the catalytic activity, in that the catalysts were active in a broad temperature range at a substantially low Mn loading, as compared to the impregnated catalyst. Particularly, the 5 wt % Mn catalyst showed the best NH(3)-SCR activity in terms of both NO(x) conversion (ca. 90%) and the amount of produced N(2)O (ca. 50 ppm) in the 200–250 °C temperature range.