Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic water splitting is crucial for sustainable energy.
• Developing efficient and cost-effective electrocatalysts is essential.
• Cobalt-based materials are promising for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).

Purpose of the Study:

• To prepare and characterize bimetallic cobalt-based coatings for HER and OER.
• To evaluate the catalytic activity and stability of these coatings in alkaline media.
• To compare their performance against pure cobalt and nickel coatings.

Main Methods:

• Facile, fast, and low-cost electroless deposition of bimetallic cobalt coatings (CoFe, CoMn, CoMo) on copper substrates.
• Characterization using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD).
• Electrochemical evaluation of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M potassium hydroxide (KOH) solution.

Main Results:

• All prepared coatings (CoFe, CoMn, CoMo, Co, Ni) exhibited activity for both HER and OER.
• The CoMo coating demonstrated the highest HER activity, achieving 10 mA·cm^-2 at a low overpotential of 61 mV.
• The pure Co coating showed the highest OER activity with a low Tafel slope of 60 mV·dec^-1.
• All coatings maintained stability under HER and OER polarization conditions.

Conclusions:

• Bimetallic cobalt coatings are effective electrocatalysts for both HER and OER in alkaline solutions.
• CoMo and Co coatings offer superior performance for HER and OER, respectively.
• These stable and cost-effective coatings present a viable alternative to traditional electrocatalysts.