Unveiling the Structural Self-Reconstruction and Identifying the Reactive Center of a V, Fe Co-Doped Cobalt...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient and stable non-noble metal electrocatalysts for water electrolysis is critical.
• Understanding active phases and surface reconstruction during reactions remains a challenge.

Purpose of the Study:

• To synthesize and characterize Fe, V co-doped Co3O4/Co(OH)2 and Co/Co(OH)2 heterointerfaces (A-Co60Fe1.1V) as bifunctional electrocatalysts.
• To investigate the role of doping and heterostructure on catalytic activity and stability for water splitting.

Main Methods:

• One-step electrodeposition and activation treatment to synthesize the catalyst.
• X-ray photoelectron spectroscopy (XPS) for elemental and valence state analysis.
• Operando Raman spectroscopy to study reaction intermediates and stability.

Main Results:

• The A-Co60Fe1.1V catalyst exhibits enhanced charge transfer due to heterointerfaces.
• Fe, V doping increases cobalt valence states, promoting HER and OER activity.
• The catalyst achieves low overpotentials for HER (51 mV) and OER (250 mV) at 10 mA cm-2.
• Operates at 1.54 V for overall water electrolysis with excellent long-term stability (>40 h).

Conclusions:

• The Fe, V co-doped Co3O4/Co(OH)2 and Co/Co(OH)2 heterointerfaces are highly active and stable bifunctional electrocatalysts.
• High-valence cobalt centers and stabilized active species (CoOOH) are key to enhanced performance.
• This work provides insights into catalyst design for efficient non-noble metal electrocatalysts.