Ammonia is a key chemical for fertilizers, industrial processes, and emerging energy applications, yet its conventional production via the Haber–Bosch process is associated with high energy demand and significant greenhouse gas emissions. In this context, electrochemical routes for ammonia synthesis have attracted increasing attention as a potential sustainable alternative, enabling nitrogen conversion under milder conditions and using renewable electricity. This review examines recent advances in electrochemical ammonia production, focusing on nitrogen reduction mechanisms, catalyst development, and electrochemical system design. The main reaction pathways for nitrogen activation are analyzed, together with the role of electrocatalysts in determining activity and selectivity. Progress in catalyst engineering, electrolyte optimization, and reactor configuration is discussed, with particular emphasis on strategies to mitigate competing reactions such as hydrogen evolution. In addition, alternative approaches based on nitrate reduction are considered due to their promising performance and potential integration with wastewater treatment. Unlike many recent reviews primarily focused on catalyst development or individual reaction pathways, this review provides an integrated perspective encompassing nitrogen reduction, nitrate reduction, electrolyte engineering, reactor architectures, and techno-economic considerations, thereby highlighting the interdependence between materials design, reaction environment, and system-level integration for scalable electrochemical ammonia synthesis.
Martín-Marroquín et al. (Sun,) studied this question.