Reducing materials to the nanoscale has a significant impact on their structure and physicochemical properties. In this context, metallic nanoparticles (NPs) are the subject of extensive research due to their unique physical properties, which make them promising candidates for the development of innovative technologies. Indeed, their nanoscale size gives them unique characteristics compared to their bulk counterparts. These characteristics are further enhanced in bimetallic alloys (or nanoalloys), where the combination of two metals within a single NP can improve or combine particular properties, thereby expanding their range of applications even further. Among the many systems studied by the scientific community, Cu-Au bimetallic NPs are nanomaterials that have been extensively investigated, particularly for their significantly enhanced catalytic properties in energy-related applications.
More interestingly, this Cu-Au system has, for us, proven to be a relatively simple yet ultimately incredibly rich system, allowing us to explore the unique physics of bimetallic nanoparticles. hus, during this seminar, I will illustrate our long-standing research on Cu-Au NPs through various examples, including i) the development of a robust methodology to determine the surface energy of bimetallic NPs, ii) the atomic-scale quantification of the chemical composition of NPs to specifically characterize fine-scale segregation effects, and finally iii) the formation of a completely exotic chemical order within equiatomic NPs. In all these examples, an approach combining state-of-the-art experiments (synthesis and advanced transmission electron microscopy) and atomic-scale numerical simulations has been adopted, along with recent developments in AI to address these topics using these truly revolutionary tools.
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[2] H. Amara et al., Phys. Rev. B. 105, 165403 (2022)
[2] G. Breyton et al., Phys. Rev. Lett. 130, 236201 (2023)
[3] G. Breyton et al., Phys. Rev. B (under review)