Pt/Au alloy nanoparticles (NPs) in a wide composition range have been synthesized by room-temperature simultaneous sputter deposition from two independent magnetron sources onto liquid PEG (MW = 600). The prepared NPs were alloyed with the face-centered cubic (fcc) structure. In addition, the particle sizes, composition, and shape are strongly correlated but can be tailored by an appropriate variation of the sputtering parameters. No individual particle but large agglomerates with partial alloy structure formed at Pt content of less than 16 atom %. Highly dispersed NPs with no agglomeration were observed in PEG when the quantity of Pt is more than 26 atom %. On the other hand, a small amount of Pt could terminate the agglomeration of Au when sputtering on the grids for transmission electron microscope observation. Our experiment and computer simulation carried out by two different methods indicate that the composition-dependent particle size of Pt/Au can be explained by the atomic concentration, formation energy of the cluster, and interaction between different metal atoms and the PEG molecule.
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http://dx.doi.org/10.1021/acs.langmuir.0c00152 | DOI Listing |
Phys Chem Chem Phys
September 2024
Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany.
Despite its well-known nobility, even platinum is subject to corrosion under the harsh conditions that many technical applications require. Based on the assumption that the platinum loss is mainly caused by the formation of volatile PtO, alloying is a promising strategy to reduce it. This investigation explores the bulk stability of Pt-Au, Pt-Ir, Pt-Re, Pt-W, Pt-Ag, Pt-Rh, Pt-Cu, Pt-Ni and Pt-Co, as well as their oxides, utilizing density functional theory, as well as and literature thermodynamic data.
View Article and Find Full Text PDFNano Lett
August 2024
Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
We present large-scale atomistic simulations that reveal triple junction (TJ) segregation in Pt-Au nanocrystalline alloys in agreement with experimental observations. While existing studies suggest grain boundary solute segregation as a route to thermally stabilize nanocrystalline materials with respect to grain coarsening, here we quantitatively show that it is specifically the segregation to TJs that dominates the observed stability of these alloys. Our results reveal that doping the TJs renders them immobile, thereby locking the grain boundary network and hindering its evolution.
View Article and Find Full Text PDFNanotechnology
February 2024
National Technical University of Ukraine 'Igor Sikorsky Kyiv Polytechnic Institute', Prospect Beresteiskyi 37, Kyiv 03056, Ukraine.
Formation of functional thin films for nanoelectronics and magnetic data storage via thermally induced diffusion-driven structural phase transformations in multilayer stacks is a promising technology-relevant approach. Ferromagnetic thin films based on Co Pt alloys are considered as a material science platform for the development of various applications such as spin valves, spin orbit torque devices, and high-density data storage media. Here, we study diffusion processes in Pt-Co-based stacks with the focus on the effect of layers inversion (Pt/Co/substrate versus Co/Pt/substrate) and insertion of an intermediate Au layer on the structural transitions and magnetic properties.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2024
Center for Photonics and Semiconductors, Institute of Semiconductor Devices and Advanced Displays, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
Throughout the development of III-nitride electronic and optoelectronic devices, electrically interfacing III-nitride semiconductors and metal schemes has been a long-standing issue that determines the contact resistance and operation voltage, which are tightly associated with the device performance and stability. Compared to the main research focus of the crystal quality of III-nitride semiconductors, the equally important contact interface between III-nitrides and metal schemes has received relatively less attention. Here, we demonstrate a comprehensive contact engineering strategy to realize low resistance to Al-rich n-AlGaN via pretreatment and metal scheme optimization.
View Article and Find Full Text PDFNat Commun
January 2024
College of Materials Science and Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, Hunan, PR China.
Stabilizing active PtNi alloy catalyst toward oxygen reduction reaction is essential for fuel cell. Doping of specific metals is an empirical strategy, however, the atomistic insight into how dopant boosts the stability of PtNi catalyst still remains elusive. Here, with typical examples of Mo and Au dopants, we identify the distinct roles of Mo and Au in stabilizing PtNi nanowires catalysts.
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