Advances in ammonia electrosynthesis from ambient nitrate/nitrite reduction

Summary

Designing genuine electrocatalysts that selectively reduce nitrate/nitrite (NO_x⁻) is becoming ever more vital to produce ammonia (NH₃) sustainably, safeguard the environment, and even rebalance the Earth's nitrogen cycle. Since 2020, the aim of NH₃ electrosynthesis from NO_x⁻ has been pursued, and with electrode design explosion, the field has been able to progressively distinguish effective strategies. Collective knowledge of state-of-the-art catalytic systems is indisputably essential for implementing this clean technology in industry. Hence, we present an overview of nicely constructed denitrifying electrocatalysts along with structural features that are more favorable for turning NO_x⁻ into NH₃, focusing on performance, mechanisms, upgraded devices, etc. Key NH₃-evolving efficiency optimization ideas with critical insights are identified and highlighted. We discuss high-quality works that exemplify gaps separating studies from large-scale deployment and proposed relevant bridging solutions. Outlook on challenges faced by NO_x⁻-to-NH₃ electrolysis systems are emphasized to inspire future works.