Multi-metal electrocatalyst with crystalline/amorphous structure for enhanced alkaline water/seawater hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Non-noble metal electrocatalysts are crucial for efficient hydrogen generation.
• Multi-metal catalysts show promise due to synergistic effects, but often suffer from poor interfacial compatibility.
• Developing catalysts with enhanced synergistic effects and stability is essential for practical applications.

Purpose of the Study:

• To design and synthesize a novel multi-metal electrocatalyst (Ni/MoO2@CoFeOx) with improved interfacial compatibility.
• To evaluate the hydrogen evolution reaction (HER) activity and stability of the developed catalyst in different alkaline media.
• To elucidate the structure-activity relationship contributing to the catalyst's enhanced performance.

Main Methods:

• Synthesis of Ni/MoO2@CoFeOx nanosheet catalyst with a crystalline/amorphous structure.
• Electrochemical characterization of HER activity, including overpotential measurements at 10 mA cm⁻² in alkaline water, alkaline seawater, and natural seawater.
• Stability testing under high current density (500 mA cm⁻²) in alkaline solution.
• In-situ Raman spectroscopy and advanced structural characterization to analyze the catalyst's properties.

Main Results:

• The Ni/MoO2@CoFeOx catalyst exhibited ultra-low overpotentials of 18 mV (alkaline water), 39 mV (alkaline seawater), and 93 mV (natural seawater) at 10 mA cm⁻².
• The catalyst demonstrated exceptional stability, maintaining performance under a high current density of 500 mA cm⁻² in an alkaline solution.
• Characterization revealed that the crystalline/amorphous interface, synergistic multi-metal interaction, enhanced conductivity, and abundant unsaturated sites contribute to high catalytic activity and stability.

Conclusions:

• The novel Ni/MoO2@CoFeOx nanosheet catalyst effectively overcomes interfacial compatibility issues in multi-metal systems.
• The catalyst's unique crystalline/amorphous structure and synergistic multi-metal effect lead to superior HER activity and stability.
• This work presents a viable strategy for designing high-performance, stable non-noble metal electrocatalysts for hydrogen production.