ELECTROREDUCTION OF NITRATE TO AMMONIA ON Co3O4/Ag2O TANDEM ELECTRODES

• Grant number: 25/03895-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2025
• End date: May 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Raphael Nagao de Sousa
• Grantee: Samuel Carlos Silva
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 24/03807-7 - Electrochemical Reduction of Nitrate to Ammonia Catalysed by Single Atoms and Metallic Oxides, AP.R

Abstract

The search for clean and sustainable energy sources has been a priority worldwide. Ammonia fits into this search as a central molecule, as it can act as a dense energy carrier. However, the need for fossil fuels for the traditional synthesis of NH3 results in worrying CO2 emissions and a significant expenditure on global energy production. The electrosynthesis of NH3 is an alternative method to the Haber-Bosch process that, in addition to being capable of generating green ammonia, can help eliminate nitrate, a pollutant in waterways resulting from the misuse of nitrogen fertilizers. This project proposes the use of electrodes composed of Co3O4 spinel with adjacent Ag2O phases in order to induce a Tandem mechanism. In this context, the formation of nitrite by the electroreduction of nitrate will be intensified by the presence of silver oxides, consecutively converted to ammonia in cobalt oxides. This material engineering strategy is expected to increase the catalytic activity and selectivity of ammonia formation, in addition to reducing the reaction overpotential. Considering that the application of negative potentials can alter the crystal structure and composition of metal oxides through electrochemical reduction, it is necessary to use in situ techniques to recognize the real active sites. For this purpose, time-resolved techniques will be used: XAS and DEMS coupled to the electrochemical cell to monitor the oxidation and coordination state of the metal atom together with the distribution of volatile products formed in the electrosynthesis of ammonia.