ELECTROCATALYTIC PRODUCTION OF GREEN AMMONIA FROM THE SELECTIVE CONVERSION OF NITROGEN OXIDES

• Grant number: 24/06318-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2024
• End date: August 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Lucia Helena Mascaro Sales
• Grantee: Isabelle Maria Duarte Gonzaga
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 21/12394-0 - Sustainable synthetic methods employing catalysis, benign solvents, safer reagents, and bio-renewable feedstock, AP.TEM
• Associated scholarship(s): 24/22463-7 - Electrochemical C-N coupling process: Urea synthesis from direct air carbon capture with nitrate wastewater, BE.EP.PD

Abstract

Nitrate is a contaminant frequently found in bodies of water. The accumulation of this substance is harmful to living beings, from the combustion of petroleum derivatives, excessive use of fertilizers and discharge of wastewater. Because of this, it is important to reduce its recurrence in the environment. However, simply reducing and eliminating is not enough, the most viable option is to go from waste treatment to the production of resources, in other words, the concept of circular economy. Several studies show that it is possible to convert nitrates into by-products of interest, such as ammonia and urea, fertilizers in agriculture. This conversion is a possible and advantageous process, but based on high-cost materials (such as platinum). Thus, this project aims to synthesize, characterize and apply electrocatalysts produced from a mixture of metallic oxides of titanium (TiO2) and copper (CuOx) since these materials are abundant on the planet, low cost and have demonstrated high activity. electrocatalytic for nitrate reduction (NO3RR). Mixed oxide films have been shown to have greater stability, activity, greater surface area, and selectivity when compared to platinum in different electrochemical processes. The oxides will be deposited on a titanium substrate to form films of the type (CuOx)y-(TiO2)1-y/Ti, varying their molar proportion to evaluate the influence of each one on the material's response. Physical characterization will be carried out using X-ray diffraction techniques, scanning electron microscopy, energy dispersive analysis and Raman spectroscopy. The electrochemical characterizations will be carried out using voltammetric techniques and electrochemical impedance spectroscopy. Furthermore, the electrocatalytic performance of NO3RR will be evaluated to produce NH3 or other by-products of interest, using materials developed on a laboratory scale. The efficiency of the electrodes in the process will be evaluated using chromatographic techniques and UV-Vis spectroscopy. Subsequently, the operational parameters for the process will be optimized. Finally, tests will be carried out in real waters with a high concentration of nitrates to analyze the feasibility of producing fertilizers for small agricultural producers.