Salting-out effect promoting highly efficient ambient ammonia synthesis.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrocatalytic nitrogen reduction to ammonia is a sustainable alternative to the Haber-Bosch process.
• Key challenges include low activity, poor selectivity, and competing hydrogen evolution.
• Limited nitrogen accessibility to electrocatalysts hinders reaction efficiency.

Purpose of the Study:

• To develop a strategy for highly efficient ammonia synthesis via electroreduction.
• To address challenges of low activity, selectivity, and hydrogen evolution.
• To investigate the impact of a salting-out effect on nitrogen electroreduction.

Main Methods:

• Utilizing a highly concentrated electrolyte to induce a salting-out effect.
• Employing solute ions with strong affinity for water molecules to form hydration shells.
• Assembling a system with a metal-free electrocatalyst for ammonia synthesis.

Main Results:

• The salting-out effect effectively suppressed hydrogen evolution.
• Enhanced nitrogen flux at the reaction interface was observed due to heterogeneous nucleation.
• A high Faradaic efficiency of 71 ± 1.9% was achieved for ammonia synthesis.
• The system demonstrated improved selectivity and activity in nitrogen electroreduction.

Conclusions:

• Triggering a salting-out effect in concentrated electrolytes is a viable strategy for efficient ammonia synthesis.
• This approach simultaneously overcomes limitations of hydrogen evolution and nitrogen accessibility.
• The developed system shows promise for practical, sustainable ammonia production.