Open Frameworks Materials for Nitrogen Electrofixation to Ammonia, Progress, Challenges, and Future Perspectives

Electrochemical nitrogen reduction (eNRR) offers a sustainable and energy-efficient alternative to the conventional Haber-Bosch process for ammonia (NH₃) synthesis, operating under mild conditions with reduced environmental impact. Open framework materials (OFMs), encompassing covalent-organic frameworks (COFs) and metal-organic frameworks (MOFs), have emerged as highly promising candidates due to their modular structures, tunable porosity, and adaptable functionalities. This review summarizes recent advancements in OFMs for eNRR, focusing on strategies for selection and design of active centers, regulation of porous structure, and conductivity enhancement strategy, as well as surface functionalization and interface engineering. Key challenges, including structural instability, low intrinsic conductivity, and the complexity of scalable synthesis, are critically analyzed. Advanced characterization methods, theoretical modeling, and machine learning are proposed as innovative tools to overcome these obstacles. Lastly, the potential for industrial-scale applications of OFMs in sustainable NH₃ production is discussed, highlighting their transformative role in eNRR.