Confinement Accelerates Water Oxidation Catalysis: Evidence from In Situ Studies

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Understanding electrocatalyst structural evolution under operating conditions is crucial for designing efficient water oxidation catalysts.
• First-row transition metal catalysts show excellent oxygen evolution reaction (OER) performance in alkaline media.
• Confinement is an emerging strategy to enhance catalyst performance.

Purpose of the Study:

• To investigate the confinement effect of Ni(OH)2 nanoparticles within the van der Waals gaps of exfoliated SnS2 (Ex-SnS2) for improved water oxidation.
• To explore the structural evolution and OER mechanism of confined Ni(OH)2 catalysts.

Main Methods:

• Synthesis of Ni(OH)2 nanoparticles confined in Ex-SnS2.
• In situ studies to probe the oxidation states of Ni during OER catalysis.
• Electrochemical measurements to evaluate OER activity and stability.

Main Results:

• The confined Ni(OH)2/Ex-SnS2 system demonstrated accelerated oxygen gas evolution compared to unconfined systems.
• The confined catalyst exhibited outstanding OER activity with an overpotential of 300 mV at 100 mA cm-2.
• Excellent stability was achieved, evidenced by a low Tafel slope of 93 mV dec-1.

Conclusions:

• Confinement of Ni(OH)2 within Ex-SnS2 vdW gaps creates a favorable environment for accelerated OER.
• The confinement effect significantly boosts OER activity and long-term durability.
• This approach offers a pathway for developing efficient and cost-effective electrocatalysts for water oxidation.