Binary FeCo Oxyhydroxide Nanosheets as Highly Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrochemical water splitting requires bifunctional catalysts active for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
• Developing cost-effective and highly active catalysts is crucial for advancing water electrolysis technology.

Purpose of the Study:

• To report a novel bifunctional FeCoOOH nanosheet catalyst for highly efficient electrochemical water splitting in an alkaline electrolyte.
• To evaluate the catalytic performance of FeCoOOH nanosheets for both HER and OER.

Main Methods:

• Fabrication of FeCoOOH nanosheet arrays directly on porous Ni foam using a simple hydrothermal method.
• Electrochemical characterization of the catalyst's activity for HER and OER in 1 m KOH.

Main Results:

• The FeCoOOH nanosheet catalyst exhibited excellent bifunctional activity for both HER and OER due to its binary oxyhydroxide structure and high electrical conductivity.
• An alkaline water electrolyzer using the FeCoOOH catalyst achieved 10 mA cm⁻² at a low cell voltage of 1.62 V without iR compensation.
• The performance of the FeCoOOH catalyst surpassed that of commercial IrO₂ and Pt/C catalysts.

Conclusions:

• The FeCoOOH nanosheet catalyst is a promising bifunctional material for efficient electrochemical water splitting.
• Direct growth on Ni foam enhances the catalyst's electrical conductivity and catalytic performance.
• This catalyst offers a potential alternative to precious metal-based catalysts for water electrolysis.