Boosted Oxygen Evolution Reactivity by Igniting Double Exchange Interaction in Spinel Oxides.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Spinel oxides are promising electrocatalysts for the oxygen evolution reaction (OER).
• Enhancing OER activity in spinel oxides is crucial for energy conversion technologies.
• The double-exchange interaction (DEI) mechanism is explored for catalytic improvement.

Purpose of the Study:

• To investigate the role of double-exchange interaction (DEI) in boosting OER activity in NiCo₂O₄ spinel oxides.
• To understand the synergistic effects of nanoheterojunctions and oxygen vacancies (V_O) on DEI.
• To evaluate the electrocatalytic performance of the engineered NiCo₂O₄.

Main Methods:

• Synthesis of NiCo₂O₄ spinel oxide nanostructures.
• Construction of nanoheterojunctions and introduction of oxygen vacancies (V_O).
• Electrochemical characterization of the oxygen evolution reaction (OER) activity.

Main Results:

• Synergistic effects from nanoheterojunctions and oxygen vacancies (V_O) ignited DEI in NiCo₂O₄.
• DEI generated superior active sites (Co^(3-δ)+ and Ni³⁺), enhancing OER.
• Achieved an overpotential of 270 ± 3 mV and a Tafel slope of 39 mV/dec, outperforming IrO₂ and RuO₂.

Conclusions:

• The engineered NiCo₂O₄ exhibits exceptional OER activity due to DEI.
• This study provides a new strategy for designing high-performance electrocatalysts.
• The findings have implications for advancing water-splitting and renewable energy technologies.