Accelerated Discovery-to-Unveiling of High-Performance and Affordable Ammonia Electrode Process by Human-Machine...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical nitrate reduction reaction (eNO3RR) to ammonia (NH3) offers sustainable fuel production and an alternative to the Haber-Bosch process.
• The complex multi-electron transfer in eNO3RR hinders affordable electrocatalyst discovery and mechanistic understanding.

Purpose of the Study:

• To establish a human-machine collaboration framework for accelerated data-driven discovery of high-performance eNO3RR electrocatalysts.
• To identify novel electrocatalysts with desirable elemental compositions for efficient ammonia synthesis.

Main Methods:

• Utilized dimensionally reduced reaction descriptors, specifically the current density difference between nitrite reduction and hydrogen evolution.
• Employed a human-machine collaboration framework for rapid electrocatalyst screening and identification.
• Conducted mechanistic studies using rotating ring-disk electrode and in situ infrared spectroscopy.

Main Results:

• Identified an optimal FeCoNiCuGa electrocatalyst with a high NH3 production rate (9.8 mmol mgcat-1 at -0.3 V vs RHE), outperforming Pt and Rh.
• Unveiled the crucial role of adsorbed nitrite (*NO2-) binding in the eNO3RR process: moderate binding accelerates NH3 formation.
• Demonstrated a drastically shortened timeframe for electrocatalyst discovery and mechanistic insight.

Conclusions:

• A comprehensive human-machine collaboration approach accelerates the discovery and understanding of promising electrode processes.
• This framework provides a feasible pathway for advancing game-changing electrochemical technologies like sustainable ammonia production.