Green Synthesis of Nitrogen-to-Ammonia Fixation: Past, Present, and Future

The nitrogen (N-2)-to-ammonia (NH3) fixation driven by renewable energy has an attractive prospect to relieve the global warming and reduce the consumption of fossil fuels. Ideally, photocatalytic, electrochemical, and photoelectrochemical approaches are developed as the next-generation NH3 synthesis technologies to substitute the Haber-Bosch method. However, the NH3 yield rate of nitrogen reduction reaction (NRR) by green approaches is extremely low, resulting in the current dilemma of NRR and contamination issues. Thus, in this mini review, the past advances on the sustainable NRR are briefly summarized in the three aspects as follows: the selectivity and adjustment of various catalysts, the type of electrolyte/solvent system, and the investigation of reaction conditions. Subsequently, the recent critical activities in the area of sustainable NH3 synthesis are analyzed and discussed deeply, and a perspective for rational and healthy development of this area is provided positively.

Automated summary

The text gives an overview of the development of nitrogen-to-ammonia synthesis driven by renewable energy and discusses the current challenges and potential solutions for the low NH3 yield rate in nitrogen reduction reactions by green methods.