Alternative Strategies Toward Sustainable Ammonia Synthesis.

As one of the world's most produced chemicals, ammonia (NH₃) is synthesized by Haber–Bosch process. This century-old industry nourishes billions of people and promotes social and economic development. In the meantime, 3%–5% of the world's natural gas and 1%–2% of the world's energy reserves are consumed, releasing millions of tons of carbon dioxide annually to the atmosphere. The urgency of replacing fossil fuels and mitigating climate change motivates us to progress toward more sustainable methods for N₂ reduction reaction based on clean energy. Herein, we overview the emerging advancement for sustainable N₂ fixation under mild conditions, which include electrochemical, photo- , plasma-enabled and homogeneous molecular NH₃ productions. We focus on NH₃ generation by electrocatalysts and photocatalysts. We clarify the features and progress of each kind of NH₃ synthesis process and provide promising strategies to further promote sustainable ammonia production and construct state-of-the-art catalytic systems. [ABSTRACT FROM AUTHOR]