Recent progress on Ti-based catalysts in the electrochemical synthesis of ammonia

Abstract

Electrochemical ammonia synthesis presents a sustainable alternative, offering the potential for enhanced energy efficiency and environmental benefits compared to the conventional Haber-Bosch process. In recent years, the electrocatalytic reduction of nitrate to ammonia (NO₃⁻RR) has emerged as a crucial approach for achieving sustainable NH₃ production. To enhance energy efficiency and successfully convert NO₃⁻ to NH₃, it is essential to investigate cost-effective electrocatalysts that provide high Faraday efficiency and demonstrate adequate stability. Ti-based materials are considered ideal candidates as catalysts due to their environmental friendliness and robust stability. This review initially summarizes the nitrate reduction reaction pathway and concisely discusses the impact of the potential intermediates and reaction steps on the overall reaction efficiency and product selectivity. Subsequently, an overview of the fundamental characteristics of Ti and TiO₂ is presented. Additionally, the research process on Ti-based electrocatalysts in the electrochemical reduction of nitrate for ammonia synthesis is summarized. Finally, the design strategies, such as heteroatom doping and the introduction of oxygen vacancies, to enhance catalytic efficiency and selectivity are presented. Through this comprehensive review, we endeavor to furnish researchers with the most recent insights into the application of titanium-based electrocatalysts in nitrate reduction reactions and to stimulate innovative thought processes on the electrocatalytic synthesis of ammonia.