Nature of Copper Active Sites in CuZSM-5: Theory Experiment

International Journal of Molecular Sciences

Ewa Broclawik²  Jerzy Datka¹  Barbara Gil¹ 

[1] Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Cracow, Poland;Institute of Catalysis, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Cracow, Poland. E-mail:

关键词: CuZSM-5;    deNOx;    active sites;    molecular modeling;    density functional theory;   

DOI  :  10.3390/i3040435

来源: mdpi

【 摘 要 】

We report here a concise resume reporting the way of constructing the model of an active site composed of transition metal cation exchanged in zeolites. The main goal was to devise the model of CuZSM-5 capable of describing geometrical and electronic properties of metal sites and adsorption complexes with small molecules. The models were built up starting from simple ring structures encountered in ZSM-5 framework to fused rings’ model selected as the representative of α position for hosting the exchanged cation. Geometrical and electronic properties of the basal model, composed of the extended framework cluster with Cu⁺ or Cu²⁺ cation, and adsorption complexes with diatomic molecules were extracted from DFT calculations. The stress was put here on direct confirmation of structural changes on copper reduction/oxidation and adsorption. Electron donor/acceptor properties of the sites combined with electronic properties of adsorbed molecules led to the proposal for the mechanism of NO activation by Cu⁺ZSM-5: transfer of electrons from copper d orbitals to antibonding states of NO should cause large weakening of the bond, which was evidenced also by IR measurements.

【 授权许可】

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