A Review on the Application of Machine Learning in Nitrogen Reduction Reaction

ABSTRACT

The electrochemical nitrogen reduction reaction (NRR) offers a promising route for sustainable ammonia synthesis under ambient conditions. Yet, its practical development remains constrained by low catalytic activity, poor selectivity against the competing hydrogen evolution reaction (HER), and the limited availability of rigorously validated experimental data. In recent years, machine learning (ML) has emerged as a powerful tool for accelerating NRR catalyst discovery by mining heterogeneous literature datasets, revealing structure–property relationships, and identifying unexplored catalyst electrolyte operating windows. This review presents a comprehensive account of ML applications in NRR, covering curated experimental databases, feature engineering based on atomic, structural, and DFT‐derived descriptors. Particular emphasis is placed on ML‐guided insights into single‐atom, dual‐atom, alloy, oxide, nitride, and defect‐engineered catalysts. Descriptor‐driven design rules are used to identify promising catalyst motifs through DFT screening and gradient‐boosted regression. The review critically examines the limitations of current ML‐assisted NRR research, including data scarcity, and the mechanistic overlap between NRR and HER. In this context, uncertainty quantification and interpretability tools such as SHAP analysis and partial dependence plots are highlighted as valuable strategies for improving model reliability. Finally, emerging closed‐loop DFT‐ML‐experiment workflows, active learning, and ML models are discussed as essential pathways toward practical, scalable ammonia electrosynthesis.