In Situ Reconstructed Crystalline-Amorphous CuNi Nanotubes Unifying Activity and Stability for Oxygen Evolution.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing durable, active, and noble-metal-free catalysts for the alkaline oxygen evolution reaction (OER) is a significant challenge.
• Conventional electrocatalysts often exhibit a trade-off between catalytic activity and long-term stability.
• Noble metal catalysts are effective but expensive and scarce for widespread OER applications.

Purpose of the Study:

• To engineer a novel electrocatalyst that reconciles the activity and stability for the alkaline OER.
• To investigate the mechanism behind the enhanced performance of the designed catalyst.
• To establish a new paradigm for designing earth-abundant OER electrocatalysts.

Main Methods:

• In situ electrochemical reconstruction of CuNi nanotubes to form a crystalline-amorphous heterostructure.
• Characterization of the catalyst's structure and composition using advanced spectroscopy (e.g., operando Raman, EELS).
• Electrochemical testing to evaluate OER activity and stability at a target current density.

Main Results:

• The synthesized CuNi nanotube catalyst exhibits a unique crystalline-amorphous heterostructure with a metallic core and amorphous oxide shell.
• The optimized catalyst achieved a low overpotential of 229 mV at 10 mA cm⁻² for alkaline OER.
• The catalyst demonstrated remarkable stability, operating continuously for over 1000 hours.

Conclusions:

• Controlled electrochemical reconstruction is a powerful strategy for developing advanced, earth-abundant OER electrocatalysts.
• The crystalline-amorphous heterostructure effectively enhances both catalytic activity and stability by optimizing charge transfer and active site density.
• This work provides a design principle for future high-performance electrocatalysts for energy conversion applications.