Decoding the electronic and structural fingerprints of single-atom catalysts via DFT-assisted XANES analysis

Area of Science:

• Catalysis
• Materials Science
• Computational Chemistry

Background:

• Single-atom catalysts (SACs) offer ultimate atomic efficiency but determining their precise structure is challenging.
• X-ray absorption near-edge structure (XANES) spectroscopy is sensitive to electronic and geometric structure but interpretation is often empirical.
• Accurate characterization of SACs is crucial for advancing catalyst design.

Purpose of the Study:

• To develop a quantitative, theory-based framework for interpreting Cu K-edge XANES spectra.
• To accurately determine the oxidation state, coordination geometry, and hydration of Cu single atoms on graphene supports.
• To establish a robust method for correlating XANES features with atomic-scale structure in SACs.

Main Methods:

• Density functional theory (DFT)-based computational spectroscopy framework.
• Quantitative interpretation of experimental Cu K-edge XANES spectra.
• Application to benchmark copper systems (Cu, Cu2O, CuO, CuSO4·5H2O) and Cu SACs on cyanographene and N-doped graphene.

Main Results:

• The computational framework accurately reproduced experimental XANES spectra for various copper systems.
• The method successfully determined the oxidation state, coordination geometry, and hydration environment of Cu single atoms on graphene.
• Direct correspondence between spectral signatures and atomic-scale structure was demonstrated.

Conclusions:

• The developed DFT-based computational spectroscopy provides a robust and transferable route for analyzing SACs.
• This methodology enables precise characterization of SACs, advancing their rational design.
• The study offers a powerful tool for understanding the electronic and structural properties of atomically precise catalysts.