Improvement of Sol-gel Method and Influence of Calcination Conditions on Properties of MnO<sub>x</sub>-CeO<sub>x</sub>/WO<sub>3</sub>/TiO<sub>2</sub>-ZrO<sub>2</sub> Catalyst

Abstract

Modified sol-gel method was adopted to prepare TiO₂-ZrO₂ carrier of molar ratio 4:1, and the catalysts were prepared by impregnating with WO₃ and MnO_x-CeO_x sequentially. The carriers and catalysts were characterized by X ray diffraction (XRD) and electron scanning electron microscopy (SEM), and their NH₃-SCR denitrification activity and sulfur resistance were investigated at low temperature. The results shown that mixing zirconium oxychloride with butyl titanate ethanol solution first and then titrating acetic acid inhibitor would have more Zr⁴⁺ substituted Ti⁴⁺ doping into the TiO₂ lattice, resulting in more lattice defects and active sites. The surface morphology of carriers were all nano particles, but the carrier prepared by modified method shown smaller particle size and better dispersion. The catalyst which was calcined at 200°C for 2.5h exhibited best NH₃-SCR performance, its denitrification activity reached 98% at 100°C, and the NO_x conversion could be maintained at about 75% after continuously injecting SO₂ (100ppm) for 8h.