DECOUPLED ELECTROCHEMICAL SYSTEMS FOR SUSTAINABLE AMMONIA ELECTROSYNTHESIS IN APROTIC MEDIA

• Grant number: 24/23525-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2025
• End date: August 31, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Cauê Ribeiro de Oliveira
• Grantee: Anelisse Brunca da Silva
• Host Institution: Embrapa Instrumentação Agropecuária. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Ministério da Agricultura, Pecuária e Abastecimento (Brasil). São Carlos , SP, Brazil

Abstract

Ammonia (NH¿) is a critical input for agriculture and the chemical industry. Still, its Haber-Bosch (H-B) production is highly energy-intensive and responsible for significant carbon emissions. Electrochemical nitrogen reduction using lithium as a mediator offers an efficient and sustainable route for ammonia synthesis. However, the high reactivity of Li with water and the need for precise control over proton generation poses significant challenges to this approach. The use of aprotic systems enhances nitrogen solubility. It effectively minimizes competition with the hydrogen evolution reaction, ensuring efficient Li recycling and improving both the reaction environment and N¿ conversion selectivity. In this context, an innovative electrolyzer is proposed, divided into three compartments (cathodic, anodic, and redox mediator), utilizing the benzoquinone/hydroquinone redox pair for ammonia production. This configuration enables continuous mediator regeneration, eliminating the need for sacrificial reagents while maintaining high efficiency and long-term stability. Additionally, the in-situ deposition of a catalytic layer and online ammonia detection via gas chromatography further optimize the process, positioning it as a promising alternative for sustainable ammonia synthesis. Combining this strategy with the reversible Li-mediated N¿ reduction addresses the limitations of traditional systems, advancing a sustainable approach to ammonia production. Aligned with the Sustainable Development Goals (SDGs) and the climate targets of COP30, this project offers an environmentally responsible solution contributing to the global energy transition. (AU)