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Investigation of the SERS and catalytic activity of plasmonic nanostructures in the degradation of organochlorine and organophosphorus pesticides

Grant number: 19/03371-6
Support type:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): April 01, 2019
Effective date (End): December 31, 2022
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Paola Corio
Grantee:Douglas dos Santos Lopes
Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:16/21070-5 - Vibrational spectroscopy with spatial resolution, AP.TEM

Abstract

Surface Enhanced Raman Spectroscopy (SERS) was first observed in 1974 by Fleischmann et. al. Since then, the SERS technique has emerged as an important tool in the detection of very small amounts of compounds of interest, thanks to the immense advantages of this tool over others well established ones, mainly due to its ultra-sensitivity, low interference of the solvent in aqueous solutions and selectivity for molecules adsorbed to a nanostructure. The main contribution to the SERS effect is consequence of plasmonic metallic surfaces, being silver and gold excellent metals for the use of SERS spectroscopic technique, since they can be excited by optical frequencies and contribute with Raman signal intensification factors that can reach between 109 to 1010 orders of magnitude under optimal excitation conditions. By combining, on the same platform, SERS and catalytic activity, it is possible to perform the in situ monitoring of several reactions. This allows one to investigate data regarding the mechanism and kinetics of the process of interest. There are several ways to obtain these bifunctional structures that can catalyze a wide range of reactions and are therefore extremely relevant for application in environmental chemistry in relation to the degradation of persistent compounds in the environment, such as organochlorine and organophosphorus pesticides. The use of these toxic compounds in huge quantities in recent years alerts to the problems they can cause to the environment and human and animal health. The present work aims to investigate the use of bimetallic plasmonic nanoparticles of AuPd immobilized in TiO2 as catalysts and SERS-active substrates in the study of the interaction between organochlorine and organophosphates pesticides on the surface of nanostructures, as well as their degradation under hydrogenation and oxidation conditions. The studies will be focused on investigating the selectivity and activity of the catalyst. (AU)