In situ/operando XAS for the study of Carbon Fiber/PAni composites for hydrogen evolution inhibition

• Grant number: 24/06899-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering
• Principal Investigator: Evaldo Jose Corat
• Grantee: Laís Gimenes Vernasqui
• Supervisor: Christina Roth
• Host Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovação (Brasil). São José dos Campos , SP, Brazil
• Institution abroad: University of Bayreuth, Germany
• Associated to the scholarship: 23/06233-9 - "In situ" and "in operando" characterization techniques on surfaces of nanostructured carbon materials, BP.PD

Abstract

Carbonaceous materials, including carbon fibers (CF), are widely applied in different electrochemical applications for their properties such as low density, good conductivity, and large surface area. Modifications, like incorporating conductive polymers such as polyaniline (PAni), can enhance their performance. Recently a novel CF/PAni/Pb composite was developed and applied as the cathode in lead-acid batteries (LAB). This composite takes advantage of Pb2+ adsorption-induced structural reorganization in PAni for inhibition of the hydrogen evolution reaction (HER). We propose extending this approach to other metallic ions for applications where HER is also a problem like CO2 (using Sn, Cu, and Co as the catalyst) and N2 reduction (using Fe as the catalyst). X-ray Absorption Spectroscopy (XAS) analysis offers insights into how metal ions integrate into the CF/PAni structure. This technique reveals coordination, local environment, and bonding of metal atoms within the composite. Besides, conducting XAS in situ/operando provides a deeper understanding of the adsorption mechanism during the electrochemical processes, supporting material development for real-world applications and bridging the gap between research and commercialization. This proposal aims to enhance our understanding of the impact of Pb and other metal ions (Sn, Cu, Co, and Fe) adsorbed onto the CF/PAni composite using in situ/operando XAS. The main aims of this investigations are: i) the electrochemical potentials needed for metal ion adsorption/desorption, and ii) structural changes during relevant electrochemical processes.