Metal-organic framework-derived sulfide-based bifunctional electrocatalyst for efficient water electrolysis in alkali...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer high surface areas and tunable porosity, making them promising for electrocatalysis.
• Challenges with pristine MOFs include limited active sites, poor charge transfer, and constrained metal center activity for water splitting.

Purpose of the Study:

• To develop an improved electrocatalyst for water splitting by addressing the limitations of pristine MOFs.
• To synthesize a layered iron-modified zinc-cobalt sulfide heterostructure on nickel foam (Ni-Fe@Zn-CoS/NF).

Main Methods:

• A three-step synthesis involving MOF array growth, hydrothermal sulfidation, and Fe-Ni electrodeposition was employed.
• The resulting sponge-like architecture was characterized for its electrocatalytic properties.

Main Results:

• The optimized Ni-Fe@Zn-CoS/NF catalyst achieved low overpotentials for hydrogen evolution (158 mV) and oxygen evolution (214 mV) at 10 mA cm⁻².
• In a symmetric electrolyzer, the catalyst reached 10 mA cm⁻² at 1.60 V for overall water splitting and maintained 95% activity over 20 hours.

Conclusions:

• The developed MOF-derived composite material significantly enhances electrocatalytic performance and long-term stability.
• This approach shows great potential for practical water electrolysis applications.