Z-Contrast Enhancement in Au-Pt Nanocatalysts by Correlative X-ray Absorption Spectroscopy and Electron Microscopy: Implications for Composition Determination

The properties of bimetallic nanoparticles (BNPs) vary widely as a function of their composition and size distributions. X-ray absorption line structure analysis is commonly used to characterize their structure, but its application to elements that are close to each other in the periodic table is hampered by poor Z-contrast. We trained an artificial neural network to recognize the partial coordination numbers in AuPt NPs synthesized via peptide templating using their X-ray absorption near-edge structure spectra. This approach, combined with scanning transmission electron microscopy analysis, revealed unique details of this prototype catalytic system that has different forms of heterogeneities at both the intra- and inter-particle levels. Our method based on the enhancement of Z-contrast of metal species will have implications for compositional studies of BNPs.

Automated summary

In this research, an artificial neural network was trained to recognize the partial coordination numbers in AuPt nanoparticles synthesized with peptide templating, and combined with scanning transmission electron microscopy analysis, unique details of the catalytic system's heterogeneity were revealed. The proposed method based on enhanced Z-contrast of metal species will have implications for compositional studies of bimetallic nanoparticles.