Structural Evolution\nof Supported Pt Atoms during\nCalcination Using Electron Atomic Pair Distribution Function: Implications\nfor Catalysis

When the size of metallic nanocatalysts is reduced to\nclusters\nor even single atoms, they can exhibit unique catalytic activity.\nUnderstanding the local atomic structure of these highly dispersed\nmetal species is crucial for comprehending changes in catalytic behavior.\nIn recent years, researchers have developed the electron pair distribution\nfunction (ePDF) method, which has been utilized to study the atomic\nshort-order arrangement of various materials. However, this technique\nhas not yet been applied to the local structure study of supported\nmetallic nanocatalysts to complement other characterization results.\nIn this study, we introduced the ePDF method to investigate nanocarbon-supported\nPt materials, which have potential applications as an oxygen reduction\nreaction catalyst. We demonstrate that with differential pair distribution\nfunction and independent component analysis, ePDF can probe the local\nstructure of supported metal species, even the single atoms, in microregions.\nThis technique was further extended to in situ experiments, indicating\nits semiquantitative capacity of studying structural evolution. The\nePDF method is expected to complement electron microscopy and extended\nX-ray absorption fine structure, providing deeper insights into the\nstructure–performance relationship of catalysts.