Evolution of Au@Pt core–shell nanoparticles at high temperatures

Abstract Bimetallic Pt nanoparticles play a critical role in various applications, including catalysis, chemical production, fuel cells, and biosensing. In this study, we start with Au@Pt core–shell structure and investigate the evolution of these nanoparticles at elevated temperatures. Our in-situ X-ray diffraction study at elevated temperatures concluded that the onset of Au–Pt alloying occurs between 500 and 600 °C. At higher temperatures, the nanoparticles gradually approached the state of a solid solution, but the composition across the nanoparticles was not uniform even at 1,000 °C. Our results suggest that the alloyed nanoparticles at high temperatures are dominated by one solid solution but contain distinct regions with slightly different compositions.