含铜MFI分子筛的H2-TPT和O2-TPD研究

 采用H2－TPR和O2－TPD手段考察了不同金属离子交换的ZSM－5分子筛催化剂上的氢还原性能和氧脱附性能．发现Cu－ZSM－5催化剂的储氧能力及氧脱附性能优于Co－ZSM－5和Fe－ZSM－5催化剂；储氧能力强、低温下氧脱附性能好的催化剂，对NO分解反应的催化活性就高．铜离子是反应的活性中心．添加Ag和Ce可使Cu－ZSM－5催化剂上氧的脱附温度大大降低．Cu－ZSM－5／堇青石整体式催化剂上Cu的存在形式与单纯的Cu－ZSM－5有差异，整体式催化剂上的一价铜数量少，但较稳定．

Studies on Cu-Containing MFI Zeolites by H2-TPR and O2-TPD

Different metal ion exchanged ZSM 5 zeolites were investigated by means of H 2 temperature programmed reduction (H 2 TPR) and O 2 temperature programmed desorption (O 2 TPD). Pure Cu ZSM 5 and in situ synthesized Cu ZSM 5/cordierite monolithic catalysts were also characterized by H 2 TPR in order to compare the oxidation states of copper ions on them. The results show that the Cu ZSM 5 catalyst has superior oxygen storage capacity than the Co ZSM 5 and Fe ZSM 5. The catalyst activity for NO decomposition is closely related to this property. Copper ions are the active sites for the reaction. The addition of Ag and Ce as promoters decreases the temperature of O 2 desorption, which indicates that adding Ag and Ce favors the O 2 desorption from the catalyst surface. The state of Cu on the Cu ZSM 5/cordierite monolithic catalyst is different from that on the pure Cu ZSM 5. Less Cu + species is found on the monolithic sample but it is more stable than that on the pure Cu ZSM 5.