Recent Advances in Nitrate Reduction Electrolyzers for Sustainable Ammonia Synthesis

The electrochemical reduction of nitrate (NO3RR) to ammonia (NH3) provides a decentralized and environmentally friendly route for sustainable ammonia production while addressing the urgent issue of nitrate pollution in water bodies. Recent advancements in NO3RR research have improved catalyst design, mechanistic understanding, and electrolyzer technology, enhancing selectivity, yield, and energy efficiency. This review explores cutting-edge developments, focusing innovative designs of catalyst and electrolyzer such as membrane electrode assemblies (MEA) and electrolyzer configuration, understanding the role of membranes in MEA designs, and various types of hybrid reactors, and membrane-free reactors. Furthermore, the integration of NO3RR with anodic oxidation reactions has been demonstrated to improve overall efficiency by generating valuable co-products. However, challenges such as competitive hydrogen evolution, catalyst degradation, and scalability remain critical barriers to large-scale adoption. We provide a comprehensive overview of recent progress, evaluates current limitations, and identifies future research directions for realizing the full potential of NO3RR in sustainable nitrogen cycling and ammonia synthesis.