Study of Cs-doped nanoparticles using solid-state Nuclear Magnetic Resonance techniques.

• Grant number: 25/09543-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: José Fabián Schneider
• Grantee: João Pedro Vilela Luz
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Company: Universidade de São Paulo (USP). Escola Politécnica (EP)
• Associated research grant: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I, AP.PCPE

Abstract

The study of ion segregation at nanomaterial interfaces has demonstrated the importance of this spontaneous thermodynamic phenomenon in controlling both the nanostructure and its properties. Examples of applications that are strongly dependent on understanding the segregation phenomenon include efficient catalysts, new-generation Li-ion batteries, and dense transparent nanometric crystalline ceramic materials for 3D printing. One analytical tool that has proven to be essential for monitoring segregation is solid-state Nuclear Magnetic Resonance (NMR). Recent work on TiO2 nanoparticles with Li addition has shown the potential of 7Li NMR for the quantitative determination of the distribution of Li+ ions in different parts of the nanostructure: surface, grain boundaries, and bulk [1,2]. The purpose of adding Li2O is to control the size of the nanostructures, but this additive also confers high ionic conduction to the materials produced, which makes these systems potentially interesting for solid-state battery technology. On the other hand, there is little knowledge about the interaction of segregated ions with the molecular-scale water layer naturally adsorbed on the surface of oxides, and how the solubility of the ions affects the ion transport mechanisms. At the same time, there is no knowledge about the mobility of segregated ions once the adsorbed water is removed. These issues will be analyzed in this project considering TiO2 nanoparticles with addition of Cs2O, using 133Cs, 1H and 1H-133Cs cross-polarization NMR techniques. The 133Cs isotope will be used as NMR probe, due to the high sensitivity of its chemical shift interaction to the chemical/structural environment of the nucleus, much higher than in the case of 7Li. (AU)