Interface-Tailored MWCNT@WO₃/NiCo₂O₄ Heterostructure Electrocatalyst for High-Performance Oxygen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen evolution reaction (OER) is a bottleneck in electrocatalyst-based water splitting (WS) for hydrogen production due to slow kinetics.
• Spinel oxide-based heterostructures (HS) supported by carbon materials offer a cost-effective strategy for OER electrocatalysis, outperforming noble metal catalysts.

Purpose of the Study:

• To develop a novel WO3/NiCo2O4 heterostructure coupled with multi-walled carbon nanotubes (MWCNT) for efficient OER electrocatalysis.
• To investigate the synergistic effects of interface engineering on the electrochemical activity and stability of the catalyst.

Main Methods:

• Ultrasonication-assisted hydrothermal synthesis was employed to create the MWCNT@WO3/NiCo2O4 heterostructure.
• Electrochemical characterization techniques were used to evaluate the catalyst's performance, including overpotential, Tafel slope, charge transfer resistance, and double-layer capacitance.

Main Results:

• The MWCNT@WO3/NiCo2O4 catalyst exhibited a low overpotential of 323 mV at 10 mA cm-2 and a Tafel slope of 123 mV dec-1.
• The heterostructure demonstrated reduced charge transfer resistance (2.5 Ω) and high electrochemical double-layer capacitance (48.9 mF cm-2).
• The catalyst showed superior electrochemical durability exceeding 38 hours.

Conclusions:

• The rational integration of WO3, NiCo2O4, and MWCNT creates a hierarchically porous heterointerface that enhances charge transport and active site accessibility.
• The developed MWCNT@WO3/NiCo2O4 heterostructure is a promising cost-effective and high-performance electrocatalyst for OER in water splitting applications.