N2O活化的Fe/ZSM-5表面活性氧的表征(英) |
Characterization of Active Surface Oxygen in N2O-activated Fe/ZSM-5 |
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摘要: |
关键词: 活性氧 Fe/ZSM-5催化剂 N2O处理 程序升温还原 [Fe-O-Fe]2+二元体 |
基金项目: |
Abstract: Temperature-programmed reduction (H2-TPR) was employed to quantitatively characterize the active oxygen species generated from a high Fe-loading Fe/ZSM-5 catalyst exposed to N2O at 250 ℃. [Fe-O-Fe]2+ dimer was determined as the active iron complex for N2O decomposition to produce the active oxygen. Reduction of Fe3+ to Fe2+ by H2 in the dimer and removal of OH- groups from Fe2+ dimer by heating Fe/ZSM-5 to 700 ℃ were the prerequisites for the formation of this active Fe complex. A linear correlation with a slope of 1.0 between the amount of [Fe-O-Fe]2+ and that of active oxygen species was observed. Maximum amount of active oxygen species can be generated by reducing Fe/ZSM-5 catalyst with H2 at the temperatures over 500 ℃ and then heating the resulting product in Ar to 700 ℃, followed by N2O exposure at 250 ℃. The ratio of the total number of oxygen atoms (Ode) deposited by interaction of [Fe-O-Fe]2+ with N2O to the amount of [Fe-O-Fe]2+ was 2. However, not all the deposited oxygen atoms were active oxygen (Oa); the ratio of Oa and Ode was 0.5. The iron dimer complex composing active oxygen is a five-atom ion [Fe2O3]2+; the most probable structure is as follows: |
Keywords: active oxygen Fe/ZSM-5 N2O treatment temperature-programmed reduction [Fe-O-Fe]2+ dimmer |
投稿时间:2005-03-06 修订日期:2005-06-10 |
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温广,张朋.N2O活化的Fe/ZSM-5表面活性氧的表征(英)[J].无机化学学报,2005,21(10):1535-1540. |
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