Sulfate-Functionalized Nickel Hydroxide Nanobelts for Sustained Oxygen Evolution.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Nickel hydroxide (Ni(OH)₂)-based electrocatalysts are cost-effective for oxygen evolution reaction (OER).
• Current Ni(OH)₂ catalysts require improved activity and durability for practical OER applications.
• Surface modification is a key strategy to enhance electrocatalyst performance.

Purpose of the Study:

• To develop a novel sulfate-functionalized Ni(OH)₂ nanobelt (S-Ni(OH)₂) electrocatalyst.
• To investigate the self-enhanced OER activity and durability of the S-Ni(OH)₂ catalyst.
• To explore the potential of a surface self-renewal strategy for electrocatalysts.

Main Methods:

• One-step hydrothermal synthesis of S-Ni(OH)₂ nanobelts directly on nickel foam (NF).
• Electrochemical characterization of the S-Ni(OH)₂/NF electrode for OER.
• Analysis of the catalyst surface evolution during the oxygen evolution reaction.

Main Results:

• The S-Ni(OH)₂/NF electrode demonstrated significantly enhanced OER activity and durability.
• A 70 mV overpotential drop was observed during 110 h of reaction at 100 mA cm^-2.
• The catalyst maintained a low overpotential of 358 mV at 200 mA cm^-2 due to surface self-renewal.
• Formation of a highly active NiOOH/Ni(SO₄)_0.3(OH)_1.4 composite was identified as the key factor.

Conclusions:

• The S-Ni(OH)₂ nanobelt catalyst exhibits superior OER performance, attributed to its self-renewing surface.
• The facile and environmentally benign fabrication process makes it promising for practical OER applications.
• The surface self-renewal strategy is a viable approach for enhancing other electrocatalysts and processes.