Upconversion LaVO4 nanoparticles combining optical thermometry and catalysis

• Grant number: 25/13764-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Paulo Cesar de Sousa Filho
• Grantee: Marine Beatriz Alves
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 22/03442-3 - 3D-NanoREV: 3D environmental studies of the microstructure engineering of vanadate-based phosphors at the nanoscale, AP.R

Abstract

Nanozymes are nanomaterials that mimic the catalytic activity of natural enzymes, offering numerous advantages such as low cost and high thermal stability despite the chemical lower specificity in comparison to the biological analogues. These properties motivate the study of inorganic nanoparticles as biomimetic catalysts. In turn, luminescent materials with nanozymatic properties emerge as promising multifunctional systems capable of acting as catalysts and in situ optical sensors. Recently, our research group demonstrated that lanthanum orthovanadate (LaVO4) nanoparticles exhibit peroxidase-like activity, making them promising candidates by combining catalysis and luminescence, especially for luminescent thermometry. Hence, this project aims to develop LaVO4 nanoparticles doped with lanthanide ions (Nd3+, Yb3+, Er3+, Eu3+) for the combination of thermometry and catalysis, exploring upconversion mechanisms under 980 and 808 nm excitation. The introduction of additional dopants (e.g. Li+ and Zr4+) will be investigated to induce structural defects in order to further improve the optical and catalytical properties. The synthesis will be carried out by direct coprecipitation in water or by colloidal conversion of rare-earth hydroxycarbonate templates to achieve structural selectivity towards monoclinic or tetragonal solids. The peroxidase-like catalytic activity will be evaluated by monitoring the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2. In summary, the goal is to develop multifunctional systems capable of integrating distinct functionalities of interest for biomedical applications of nanomaterials.