Cu/SAPO-34催化剂的NH_3-SCO活性及抗水热性能研究

Catalytic performance and hydrothermal stability of Cu/SAPO-34 catalyst in the selective catalytic oxidation of NH_3

采用浸渍法制备了一系列不同铜含量的Cu/SAPO-34催化剂,考察了该系列催化剂上NH_3选择性催化氧化反应性能(NH_3-SCO)。实验结果表明,10%-Cu/SAPO-34催化剂在300℃温度下具有100%的NH_3去除率,且其氮气选择性大于90%。与此同时,通过XRD、BET、UV-vis、H_2-TPR和XPS等表征分析结果表明,高度分散的CuO是Cu/SAPO-34催化剂的主要活性组分。对10%-Cu/SAPO-34催化剂进行水热处理后,催化剂低温活性明显提高,催化剂的N_2选择性在325℃急剧下降。这是由于水热处理导致一定数量的铜物种发生迁移并且形成了更稳定的铜物种引起。SAPO-34的骨架结构遭到一定程度的破坏。

A series of Cu/SAPO-34 catalysts for ammonia selective catalytic oxidation( NH_3-SCO) were prepared by impregnation method. The results of activity test indicated that the NH_3 conversion over 10%-Cu/SAPO-34 catalyst was nearly 100% at 300 ℃ and N_2 selectivity was more than 90% in the range of test temperature. Meanwhile,the characterization results of XRD,BET,UV-vis,H_2-TPR and XPS showed that the highly dispersed CuO species in Cu/SAPO-34 catalyst were the main active component. Furthermore,the aged 10%-Cu/SAPO-34 catalyst performed better NH_3-SCO activity at low temperature,while the N_2 selectivity dramatically decreased at 325 ℃,SAPO-34 zeolite crystallinity would deteriorate under hydrothermal treatment.