Low-Temperature Selective Catalytic Reduction of NO with NH3 Over Mn-Fe Mixed Metal Oxides on the Nitric Vapor Functionalized Carbon Nanotubes Prepared by a Polyol Process

Highly dispersed Mn-Fe mixed metal oxides were supported on the nitric vapor functionalized carbon nanotubes (CNTs) by the polyol process for the low-temperature selective catalytic reduction (SCR) of NO with NH3. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and Fourier transform infrared (FT-IR) spectroscopy have been used to elucidate the structure and surface properties of the obtained catalysts. It was found that the Mn-Fe/VF-CNTs catalysts synthesized by the polyol process exhibited higher activity and more extensive operating-temperature window, compared to the catalysts prepared by the impregnation method. On the basis of the catalyst characterization, the better dispersion of metal oxides on the CNTs surface, the more chemisorbed oxygen species, the higher Mn4+/Mn and Oα/Oα+Oβ ratios played key roles in the excellent catalytic performance of the catalyst in the low-temperature SCR of NO to N2 with NH3.