Structural Evolution of Supported Pt Atoms during Calcination Using Electron Atomic Pair Distribution Function: Implications for Catalysis

When the size of metallic nanocatalysts is reduced to clusters or even single atoms, they can exhibit unique catalytic activity. Understanding the local atomic structure of these highly dispersed metal species is crucial for comprehending changes in catalytic behavior. In recent years, researchers have developed the electron pair distribution function (ePDF) method, which has been utilized to study the atomic short-order arrangement of various materials. However, this technique has not yet been applied to the local structure study of supported metallic nanocatalysts to complement other characterization results. In this study, we introduced the ePDF method to investigate nanocarbon-supported Pt materials, which have potential applications as an oxygen reduction reaction catalyst. We demonstrate that with differential pair distribution function and independent component analysis, ePDF can probe the local structure of supported metal species, even the single atoms, in microregions. This technique was further extended to in situ experiments, indicating its semiquantitative capacity of studying structural evolution. The ePDF method is expected to complement electron microscopy and extended X-ray absorption fine structure, providing deeper insights into the structure–performance relationship of catalysts.