Expansion of studies on inhibition of hydrogen evolution reaction in electrochemical processes through polyaniline and metal ion composites

• Grant number: 24/22086-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2025
• End date: August 31, 2026
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Evaldo Jose Corat
• Grantee: Camila Alves Escanio
• Host Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovação (Brasil). São José dos Campos , SP, Brazil
• Associated research grant: 19/18572-7 - New carbon materials: their relevant space, environmental and relevant spin off applications, AP.TEM

Abstract

Carbon materials are widely used in different electrochemical applications due to their properties, such as low density, good conductivity and large surface area. However, they have a very low threshold for the hydrogen evolution reaction (HER), negatively impacting electrochemical processes. In many cases, such as in flow redox batteries, losses due to HER are common. Another subject of great interest where HER has a significant impact is in electrochemical processes of CO2 and N2 reduction. Therefore, HER inhibition is important and needs to be further studied. Our group developed a method for HER inhibition, specifically for use in lead-acid batteries, by coating the carbon with a polyaniline (PAni) composite and adsorbing lead ions, the PAni/Pb composite [1]. This composite takes advantage of the structural reorganization induced by Pb2+ adsorption on PAni to inhibit HER. In this project, we propose to extend this approach to other metal ions for applications where HER is also a problem, such as vanadium flow redox batteries (using V2+), CO2 reduction (using Sn2+, Cu2+ and Co2+, where these metals are typical catalysts), N2 reduction (using Fe2+ which is the typical catalyst). For example, Fe2+ has already been tested and it inhibits HER. This proposal will be developed concomitantly with work abroad, in cooperation with Dr. Cristina Roth at the Faculty of Engineering Science - Bayreuth University. The work abroad will focus on "in operando" characterizations, by XAS and soft XAS. Here we will focus on electrochemical solutions. The following will be investigated: i) the electrochemical potentials required for adsorption/desorption of metal ions and ii) changes in the potentials for HER, iii) evaluation of applicability in different processes.