Efficient N₂ electroreduction enabled by linear charge transfer over atomically dispersed W sites

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic nitrogen reduction reaction (NRR) offers a sustainable alternative to the Haber-Bosch process for ammonia (NH3) production.
• Developing efficient NRR catalysts and understanding their mechanisms are significant challenges.

Purpose of the Study:

• To design and synthesize novel atomically dispersed tungsten (W) catalysts for enhanced NRR.
• To investigate the relationship between charge transfer and NRR performance.
• To elucidate the catalytic mechanism of W-based catalysts for ammonia synthesis.

Main Methods:

• Atomically dispersed W atoms were embedded into V2-xCTz using a self-capture method.
• Electrocatalytic performance was evaluated by measuring ammonia yield and Faradaic efficiency (FE).
• Density Functional Theory (DFT) computations were employed to study reaction mechanisms and energy barriers.

Main Results:

• The n-W/V2-xCTz catalyst achieved a record ammonia yield of 121.8 μg h-1 mg-1 and FE of 34.2% at -0.1 V vs RHE.
• DFT calculations showed synergistic effects of neighboring W atoms, lowering the limiting potential (UL) to 0.32 V.
• A linear relationship between UL and integrated-crystal orbital Hamilton population (ICOHP) was established as an activity descriptor.

Conclusions:

• Atomically dispersed W catalysts exhibit exceptional performance for electrocatalytic NRR.
• Neighboring single atoms play a crucial role in enhancing reaction kinetics through synergistic effects.
• The study provides a new descriptor for NRR activity and insights into the underlying electronic structure-performance relationship.