Hydrogen Evolution Performance Under High Current Densities of Crystalline/Amorphous NiMo/NM Electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is crucial for clean energy technologies.
• Nickel-molybdenum (NiMo) alloys show promise as cost-effective alternatives to platinum-group metals.
• Controlling the nanostructure and phase composition of NiMo catalysts is key to enhancing their performance.

Purpose of the Study:

• To synthesize and characterize a novel NiMo alloy catalyst with a heterogeneous crystalline-amorphous structure.
• To evaluate the electrocatalytic activity and stability of the NiMo catalyst for HER in alkaline media.
• To investigate the relationship between the catalyst's morphology, structure, and HER performance.

Main Methods:

• One-step electrodeposition of NiMo alloy on a Ni mesh substrate.
• X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) for structural and compositional analysis.
• Scanning electron microscopy (SEM) for surface morphology characterization.
• Electrochemical testing (e.g., HER polarization curves) in alkaline solutions.

Main Results:

• The electrodeposition yielded NiMo alloy catalysts (NiMo/NM) with a unique coexistence of crystalline and amorphous phases.
• SEM revealed a "cauliflower-like" surface morphology, increasing specific surface area and active sites.
• The NiMo/NM catalyst demonstrated superior HER activity and long-term stability in alkaline solutions compared to commercial Pt/C.
• Excellent catalytic stability was observed under high current densities and in simulated alkaline seawater electrolytes.

Conclusions:

• The heterogeneous crystalline-amorphous structure and rough surface morphology of NiMo/NM catalysts significantly enhance HER performance.
• NiMo/NM catalysts offer a promising, stable, and highly active alternative to precious metal catalysts for industrial HER applications.
• The structural integrity of the NiMo alloy contributes to its remarkable catalytic stability in challenging environments.