Amorphization engineering of Ni-cysteine coordination composition for urea electro-oxidation at large current density

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Urea-assisted hydrogen generation is hindered by the oxygen evolution reaction (OER) and inefficient Ni3+ active site formation.
• Developing catalysts that suppress OER and promote Ni2+ to Ni3+ conversion is crucial for efficiency.

Purpose of the Study:

• To design an efficient urea electro-oxidation reaction (UOR) catalyst by constructing amorphous Ni-cysteine coordination (aNi-cys).
• To suppress competitive OER and promote Ni2+ to Ni3+ in-situ electrochemical configuration.

Main Methods:

• Synthesized amorphous Ni-cysteine coordination (aNi-cys) by regulating the Ni/l-cysteine coordination environment.
• Investigated the catalyst's performance in urea electro-oxidation and its stability.

Main Results:

• The aNi-cys catalyst demonstrated high UOR activity with a peak current density of 263 mA cm-2, surpassing crystalline Ni-cysteine coordination (cNi-cys).
• Achieved long-term stability for 50 hours and significant energy savings (8 kWh/kg H2) in simulated seawater electrolysis.

Conclusions:

• Amorphous Ni-cysteine coordination effectively suppresses OER and enhances UOR activity through optimized electronic structure and increased active sites.
• This work provides a strategy for advanced electrocatalyst preparation for urea-related energy systems demanding high current densities.