A Mo-guided self-reconstructed highly active NiOOH catalyst for a durable alkaline oxygen evolution reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Alkaline water electrolysis (AWE) is crucial for sustainable hydrogen fuel generation.
• Key challenges in AWE include slow oxygen evolution reaction (OER) kinetics and limited electrode durability.

Purpose of the Study:

• To develop a highly active and stable pure nickel-based electrocatalyst for the oxygen evolution reaction in AWE.
• To investigate the mechanism behind the enhanced performance using in situ spectroscopic techniques.

Main Methods:

• A facile Mo-guided self-reconstruction strategy was employed to synthesize the nickel oxyhydroxide catalyst on nickel foam (γ-NiOOH_Mo-SR/NF).
• Electrochemical performance was evaluated using techniques like linear sweep voltammetry and chronoamperometry.
• In situ spectroscopic studies were conducted to probe the catalyst's surface and reaction intermediates.

Main Results:

• The synthesized γ-NiOOH_Mo-SR/NF catalyst demonstrated excellent OER activity and remarkable long-term stability (>1100 h at 1.0 A cm^-2 and >100 h at 3.0 A cm^-2).
• The catalyst's performance was attributed to in situ generated high-valent Ni sites and an interfacial hydrogen-bonding network.
• The hydrogen-bonding network facilitated hydroxide ion transport and mitigated local acidification, enhancing OER efficiency.

Conclusions:

• The Mo-guided self-reconstruction strategy effectively produces a superior nickel-based OER electrocatalyst.
• The developed catalyst significantly advances the efficiency and stability of alkaline water electrolysis for green hydrogen production.
• This approach provides valuable insights for designing next-generation non-precious metal electrocatalysts.