焙烧程序对一步合成Cu-SSZ-13催化剂NH3-SCR性能的影响

焙烧程序影响一步合成法制备Cu-SSZ-13催化剂中Cu物种的种类及分布，是影响催化剂在NH₃选择性催化还原（NH₃-SCR）氮氧化物反应中催化性能的重要因素。为研究焙烧程序对该方法制备Cu-SSZ-13催化剂性能的影响，采用不同的焙烧温度及升温速率制备Cu-SSZ-13催化剂，并考察各催化剂的催化活性、水热稳定性及活性物种形态。结果表明焙烧温度不改变催化剂的晶型结构，但影响催化剂的活性物种形态及稳定性。当焙烧温度为600℃时，催化剂中Cu物种全部为孤立的Cu²⁺，并具有极高的稳定性，催化剂具有最佳的活性及水热稳定性。固定焙烧温度为600℃，随升温速率的提高，催化剂活性及水热稳定性表现出下降趋势，考虑经济成本，最佳的升温速率应为1℃/min。因此，以1℃/min的升温速率升至600℃焙烧6h是一步合成法制备Cu-SSZ-13催化剂的最佳焙烧程序，所得催化剂具备优异的NH₃-SCR活性和水热稳定性。

Influence of calcination procedure on the one-pot synthesized Cu-SSZ-13 catalysts and their performance in NH3-SCR

The calcination procedures affected the state and the distribution of Cu species in the one-pot synthesized Cu-SSZ-13,which then influenced their catalytic performance greatly. In order to investigate the effect of calcination procedure on the Cu-SSZ-13 in the selective catalytic reduction of NO_x by ammonia(NH₃-SCR),we prepared the catalysts with different temperatures and ramp rates. The catalytic activity and hydrothermal stability and state of active species of the catalysts were tested. The calcination temperature did not change the structure of the catalyst,but affected the state and the stability of the active species. When the temperature was set at 600℃,all Cu species in the catalyst were isolated Cu²⁺ with excellent stability,and the catalyst showed the best catalytic performance and hydrothermal stability. When the temperature was fixed at 600℃,the activity and hydrothermal stability of the catalysts decreased with the increase of ramp rate. Considering the cost,we had better set the ramp rate as 1℃/min. Thus,the optimal procedure was to calcine sample at 600℃ for 6h with a ramp rate of 1℃/min,and the catalyst showed the best NH₃-SCR activity and the highest hydrothermal stability.