Electrocatalytic green ammonia production beyond ambient aqueous nitrogen reduction

Ammonia (NH3), the second highest produced chemical in the world, is dominantly used for fertilizer pro-duction to underpin the modern agriculture, and recently attracts increasing interest as an energy-dense, carbon-neutral carrier for renewable energy. The present Haber-Bosch process for NH3 production is energy-, emission-, and capital-intensive. Therefore, recent research efforts have been devoted to developing efficient alternatives with decreased carbon emissions, higher compatibility with renewables, and flexible operation. Electrocatalysis technologies represent a crucial role and great potentials, especially the electrocatalytic nitrogen reduction reaction (NRR). However, the achieved performance is still far from feasibility due to the intrinsic limitations from nitrogen activation and reaction system. In this Review, we first discussed the roadmap towards green NH3, critically assessed the challenges of NRR, and then focused on several emerging strategies beyond conventional catalyst design and engineering under ambient aqueous conditions, including electrolyte effect, operation pressure, Li-mediated reaction, reactor innovation, new N-transformation reactions, and redox-mediated catalysis. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Ammonia is the second highest produced chemical in the world and is used for fertilizer production and as a carrier for renewable energy. The current production process for ammonia has high energy consumption, emissions, and capital investment, leading to the need for efficient alternatives. Electrocatalysis technologies, particularly the nitrogen reduction reaction, have great potential but face intrinsic limitations. This review discusses the roadmap towards green ammonia and explores emerging strategies beyond conventional catalyst design and engineering.