Electrocatalytic activity of layered double hydroxides decorated with plasmonic nanoparticles

• Grant number: 23/16671-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2024
• End date: April 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Susana Inés Córdoba de Torresi
• Grantee: Jéssica Alves Nogueira
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/00675-4 - Tying up materials for electrochemical energy storage and catalysis, AP.TEM

Abstract

The energy transition from a fossil fuel-dependent economy to one based on renewable sources requires the development of efficient and durable energy conversion devices, such as batteries, electrolyzers, and fuel cells. The widespread use of these electrochemical devices is limited by the kinetic constraints of the redox reactions occurring within them and the high cost of materials used as electrodes. To address this issue, research on low-cost and abundant electrocatalysts capable of achieving high current densities at low overpotentials is crucial. In this context, electrocatalysts of nickel and iron (oxy)hydroxides, especially layered double hydroxides (LDH), emerge as a new and exciting alternative for various electrochemical reactions in an alkaline environment. In this project, we propose an innovative approach to enhance the activity of these materials by modifying them through the anchoring of nanoparticles with a recognized plasmonic effect when irradiated with visible light. Our goal is to synthesize NiFe-LDHs using two methods, coprecipitation and microfluidics, and then modify them by adding gold and silver nanoparticles. Electrons on the surface of these nanoparticles become excited when irradiated with light, with gold and silver standing out for their excitation in the visible region, allowing the use of sunlight to promote the effect. The materials will be characterized using a comprehensive set of characterization techniques, including Raman spectroscopy, electron microscopy, and X-ray diffraction, with state-of-the-art equipment available at IQ-USP. Using traditional electrochemical characterization techniques such as cyclic voltammetry, polarization curves, and impedance, we will evaluate the electrocatalytic activity of these materials for four relevant reactions in the energy transition: oxygen evolution reaction, hydrogen evolution reaction, CO2 electroreduction, and ethanol electro-oxidation. The ultimate purpose is to determine the relationships between structure, composition, and activity of the materials, in dark and illuminated conditions. The knowledge gained with this project will be crucial for the applicability of NiFe-LDHs as electrocatalysts in electrochemical devices.