CeO2 Nanoparticle-Loaded MnO2 Nanoflowers for Selective Catalytic Reduction of NOx with NH3 at Low Temperatures

CeO2nanoparticle-loaded MnO2nanoflowers, prepared by a hydrothermal method followed by an adsorption-calcination technique, were utilized for selective catalytic reduction (SCR) of NOxwith NH3at low temperatures. The effects of Ce/Mn ratio and thermal calcination temperature on the NH3–SCR activity of the CeO2-MnO2nanocomposites were studied comprehensively. The as-prepared CeO2-MnO2catalysts show high NOxreduction efficiency in the temperature range of 150–300 °C, with a complete NOxconversion at 200 °C for the optimal sample. The excellent NH3–SCR performance could be ascribed to high surface area, intimate contact, and strong synergistic interaction between CeO2nanoparticles and MnO2nanoflowers of the well-designed composite catalyst. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) characterizations evidence that the SCR reaction on the surface of the CeO2-MnO2nanocomposites mainly follows the Langmuir–Hinshelwood (L-H) mechanism. Our work provides useful guidance for the development of composite oxide-based low temperature NH3–SCR catalysts.Keywords:Mn-Ce mixed oxide;ion-adsorption;selective catalytic reduction;NOxconversion