Improvement of Sol-gel Method and Influence of Calcination Conditions on Properties of MnO_x-CeO_x/WO_3/TiO_2-ZrO_2 Catalyst

摘要

Modified sol-gel method was adopted to prepare TiO_2-ZrO_2 carrier of molar ratio 4:1, and the catalysts were prepared by impregnating with WO_3 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 NH_3-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 Zr~(4+) substituted Ti~(4+) doping into the TiO_2 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℃ for 2.5h exhibited best NH_3-SCR performance, its denitrification activity reached 98% at 100℃, and the NO_x conversion could be maintained at about 75% after continuously injecting SO_2 (100ppm) for 8h.