High Efficiency of Ce-Modified ${\mathrm{MnO}}_{\mathit{x}}/{\mathrm{TiO}}_2\text{-}{\mathrm{ZrO}}_2$-Based Low-Temperature Selective Catalytic Reduction Denitration Catalysts

The Mn-based denitration catalyst has problems such as structural instability and poor poison resistance. In this work, Ce-modification improved the ${\mathrm{NO}}_x$ conversion and sulfur resistance of Mn-based catalysts. The ${\mathrm{TiO}}_2\text{-}{\mathrm{CeO}}_2$, ${\mathrm{ZrO}}_2\text{-}{\mathrm{CeO}}_2$ and ${\mathrm{TiO}}_2\text{-}{\mathrm{ZrO}}_2\text{-}{\mathrm{CeO}}_2$ (molar ratio of $4:1:n$) carriers were prepared by the sol–gel method, then ${\mathrm{MnO}}_x$ was impregnated on ${\mathrm{TiO}}_2\text{-}{\mathrm{ZrO}}_2\text{-}{\mathrm{CeO}}_2$ to investigate the catalytic activity and ${\mathrm{SO}}_2$ resistance at low temperature. The as-synthesized catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) to show the microstructure of the catalyst and the effect of Ce on the denitration performance. The results demonstrated that the addition of Ce into the ${\mathrm{TiO}}_2\text{-}{\mathrm{ZrO}}_2$ carrier inhibited the growth of ${\mathrm{TiO}}_2$ grains, formed ${\mathrm{CeTi}}_2{\mathrm{O}}_6$ crystals, improved the content of ${\mathrm{Mn}}^{4+}$, and increased the adsorption of ${\mathrm{NH}}_3$, and thus the ${\mathrm{NO}}_x$ conversion efficiency was improved. In the presence of both ${\mathrm{SO}}_2$ and ${\mathrm{H}}_2\mathrm{O}$, the addition of Ce lowered the formation amount of ammonium sulfate and avoided the sulfation of manganese. The results suggest that Ce improved the structural instability and poison-resistance of Mn-based catalysts.