Optimization of Hybrid Crystal with SAPO-5/34 on Hydrothermal Stability for deNOx Reaction by NH3

Abstract

In order to deal with the challenge of the hydrothermal deactivation of selective catalytic reduction of NOx by NH3(NH3-SCR) catalyst and extend its lifetime, a novel Cu/SAPO-5/34 catalyst was prepared, and it almost maintains its deNOx performance with a high conversion rate of 90% NOx between 175 °C and 400 °C after undergoing the rigorous treatment at 800 °C for 12 h. Thus, Cu/SAPO-5/34 is more recalcitrant to the high-temperature hydrothermal deactivation than Cu/SAPO-34. Besides, the formation of N2O is always below 3×10−6(3 ppm) during the whole reaction temperature, performing an advanced catalytic selectivity. The effect of high-temperature hydrothermal treatment on the morphology, structure and texture property, the acid sites, as well as the active copper species were investigated. These characterizations manifest that the optimized high-temperature hydrothermal stability is associated closely with the good structural stability over Cu/SAPO-5/34-HT, which facilitates to preserve reaction sites, and then showing the better hydrothermal stability than Cu/SAPO-34.