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Findings
In recent years, X-ray absorption spectroscopy (XAS) has emerged as an essential technique for investigating the structure and composition of heterogeneous catalysts, providing valuable insights into the nature of active sites within these systems. However, the inherently averaged XAS signal, which encompasses all absorber-containing species formed during in situ/operando experiments, often complicates data interpretation. To address this challenge, advanced analytical methods have been developed.
In this study, we employed in situ XAS spectroscopy in combination with multivariate curve resolution-alternating least squares (MCR-ALS) and wavelet transform (WT) analysis to track the evolution of distinct Cu species in histidine-modified Cu-UiO-66 MOFs and gain detailed structural insights into the Cu sites.
A key innovation in this work was the application of density functional theory (DFT)-assisted extended X-ray absorption fine structure (EXAFS) fitting to quantitatively refine the local structure of individual Cu species in the Cu-UiO-66 MOFs. Additionally, DFT calculations revealed that Cu(II) ions coordinated within defective Zr clusters exhibit greater redox activity than those bound to histidine ligands.
Published: 6th Februay 2025, https://pubs.acs.org/doi/10.1021/acs.jpcc.4c08029
Funding
European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 856446 (CUBE)) .
Research Council of Norway through the Centre of Excellence (No. 262695) and Sigma2 for computational resources (No. nn4654k) .