Cu-exchanged zeolites are attracting increasing attention as platforms for high-impact selective redox chemistry, including NH₃-mediated selective catalytic reduction of harmful nitrogen oxides (NH₃-SCR) and selective oxidation of methane to methanol (MTM). X-ray absorption spectroscopy (XAS) today represents a well-established and widespread technique for the characterization of these systems, but open challenges remain to accurately determine nuclearity and chemical identity of Cu-oxo species stabilized under high-temperature oxidative conditions. To systematically assess limitations and potential of XAS in this context, here we consistently explored by DFT a set of monomeric and dimeric Cu^II species incorporated in the chabazite (CHA) and mordenite (MOR) frameworks, envisaged as key players for both NH₃-SCR and MTM. We present a combined DFT-assisted analysis based on both full-potential XANES simulation and Wavelet Transform Analysis (WTA) applied to computed EXAFS signals. The resulting theoretical insights set the bases for an easier and more robust interpretation of the XAS data collected on Cu-zeolite systems. In particular, we evidenced possible fingerprint features in the XANES region, together with the difficulties in discriminating among monomeric and dimeric Cu^II moieties solely based on their XANES signatures. We then show the potential of Wavelet Transform Analysis as a new tool in the identification and visualization of EXAFS atomic contributions, to possibly enhance the EXAFS sensitivity to the nuclearity of Cu-oxo species in Cu-zeolites.

作为高影响力选择性氧化还原化学的平台，铜交换沸石正受到越来越多的关注，包括NH ₃介导的有害氮氧化物的选择性催化还原（NH ₃ -SCR）和甲烷选择性氧化为甲醇（MTM）。如今，X射线吸收光谱法（XAS）代表了这些系统表征的一种成熟且广泛使用的技术，但是要准确确定在高温氧化条件下稳定的Cu-氧代物质的核和化学特性，仍存在挑战。为了系统地评估在这种情况下XAS的局限性和潜力，在这里我们通过DFT不断探索了一组单体和二聚Cu ^II菱沸石（CHA）和丝光沸石（MOR）框架中掺入的物种，被认为是NH ₃ -SCR和MTM的主要参与者。我们提出了基于全势XANES模拟和应用于计算出的EXAFS信号的小波变换分析（WTA）的组合DFT辅助分析。由此产生的理论见解为更轻松，更可靠地解释在Cu沸石系统上收集的XAS数据奠定了基础。特别是，我们证明了XANES区域可能存在的指纹特征，以及难以区分单体和二聚体Cu ^II的困难。部分仅基于其XANES签名。然后，我们展示了小波变换分析作为EXAFS原子贡献的识别和可视化的一种新工具的潜力，以可能增强EXAFS对Cu-沸石中Cu-氧代物种核化的敏感性。