Effect of calcination temperature on catalytic activity of Cu/ZSM5

In order to study the effect of calcination temperature on catalytic efficiency of zeolite catalyst, the ZSM5 zeolite supported copper catalysts were prepared by the impregnation method via different calcination temperatures. And the catalytic activities of these catalysts were tested by the NO selective catalytic reduction reaction. The catalysts were characterized by various techniques, including X-ray diffraction (XRD), scanning election microscopy (SEM) and N2 physisorption experiments. The results showed that the catalysts calcined at 500 ℃ exhibited the best selective catalytic reduction (SCR) activities, and the NOx conversion reaches above 95% between 180 ℃ and 300 ℃. While the catalysts calcined at 600 ℃ or 700 ℃ showed poor SCR activities. The catalysts calcined at 500 ℃ had the largest specific surface areas 299 m2/g and flourishing pore structure. When the calcination temperatures were beyond to 600 or 700 ℃, the catalysts became sintered and its specific surface areas reduced, which were not conducive to catalytic reaction. At the same time, the research shows that the Cu/ZSM5(500) catalyst has good sulfur dioxide resistance. At 210 ℃,the denitration efficiency of the catalyst can reach more than 89% under the volume fraction of 300×10-6 sulfur dioxide, while the catalyst is continuously operated for 180 hours at 270 °C and a volume fraction of 400×10-6 sulfur dioxide, its denitration efficiency still remains above 88%.