Local Structural Investigation of Mechanochemically Synthesized Multimetallic Nanoparticles by X-ray Absorption Spectroscopy and X-ray Total Scattering Techniques.

• Grant number: 25/13507-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: September 01, 2025
• End date: February 28, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Paulo Filho Marques de Oliveira
• Grantee: Ismael Pinheiro Lucas Xavier
• Supervisor: Ana de Oliveira Guilherme Buzanich
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Bundesanstalt Für Materialforschung Und -Prüfung, Germany
• Associated to the scholarship: 23/01223-5 - Mechanochemistry as a tool in the preparation of multimetallic nanomaterials, BP.DD

Abstract

Metallic nanoparticles exhibit an intrinsic structure-property relationship, where controlling their structure directly influences their applications, such as in catalysis and sensing. In some cases, combining noble metals (Ag, Au, and Pd) with less noble metals (Cu and Ni) represents a powerful strategy to integrate multiple metallic properties into multimetallic nanoalloys. Although the solvothermal synthesis method is the most commonly used, scalability and cost issues limit its applicability. For this reason, the mechanochemical approach emerges as a solvent-free and eco-friendly alternative. The mechanosynthesis of multimetallic nanoparticles has become a promising field for developing new materials. However, challenges related to understanding the formation mechanisms of these materials, along with the limited knowledge of their atomic organization at the local level, make the rational design of materials highly complex. To address this, the present project proposes the use of X-ray scattering and absorption techniques to probe the formation of multimetallic nanoparticles composed of Ag, Au, Pd, Cu, and Ni. The synthesis will be carried out via ball milling, while XANES, EXAFS, and SAXS techniques will be employed to monitor the chemical and structural changes occurring in the early stages of nanoparticle formation. Additionally, PDF modeling of X-ray total scattering data will be used to access the local structure of these materials. The goal is to gain new insights into the influence of mechanical action on nanomaterial formation and the mechanisms underlying their atomic organization.