NO分解催化剂Cu/分子筛的ESR研究 Ⅰ.水合铜分子筛的ESR研究

ESR Studies on Cu/Zeolite Catalyst for NO Decomoposition Ⅰ ESR Studies on Hydrated Cu/Zeolite

系统地比较了在各种不同制备条件下制得的Ｃｕ／ＺＳＭ－５、Ｃｕ／丝光沸石、Ｃｕ／镁碱沸石和Ｃｕ／毛沸石的ＥＳＲ谱，至少六种水合Ｃｕ物种被发现，而且发现分子筛的腔结构对Ｃｕ物种的存在状态有很大的影响。

Using ESR technique,the author has found at least 6 kinds of Cu species in Cu/zeolite ESR spectra of hydrated Cu/ZSM 5 samples,recorded at room temperature,exhibited a signal with g 1 iso =2 159 Such a symmetry signal was indicative of a mobile species At temperature of liquid N 2,the ESR spectrum of hydrated Cu/ZSM 5 exhibited a drastic change Owing to the motion of [Cu(H 2O) 6] 2+ being frozen and [Cu(H 2O) 6] 2+ being anchored to the ZSM 5 oxygen wall,an axial g anisotropy singal with g 2 ∥=2 380 and A 2 ∥=143 5G appeared At room temperature,ESR spectra of Cu/mordenite also exhibited the symmetry signal with g 6 iso =2 143 By decreasing temperature to that of liquid N 2,an axial g anisotropy signal appeared immediately On Cu/ferrierite,two kinds of immobile species at room temperature were found with g 4 ∥=2 381, A 4 ∥=131 4G and g 5 ∥=2 317,A 5 ∥=171 7G respectively Only a Cu species with g 4 ∥=2 382,A 4 ∥=131 3G was found on Cu/erionite These results show the size and structure of zeolite cavities have important effect on the structures and states of Cu species on zeolite