Tailored Cation Distribution in High-Entropy Mn-Co-Ni-Cu-Zn Oxides: Toward Advanced OER Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Water splitting is crucial for renewable energy and energy storage.
• Developing efficient, cost-effective electrocatalysts for the oxygen evolution reaction (OER) is a key challenge.
• High-entropy oxides (HEOs) are emerging nanomaterials with complex structures and significant potential.

Purpose of the Study:

• To synthesize a layered (MnCoNiCuZn)O high-entropy oxide (HEO) using a metal-organic framework (MOF)-assisted strategy.
• To evaluate the impact of cation concentration on OER performance.
• To investigate the potential of HEOs as advanced electrocatalysts for water splitting.

Main Methods:

• Synthesis of (MnCoNiCuZn)O HEO via a MOF-assisted strategy.
• Characterization of chemical bonding and electronic conductivity using XPS and EDS mapping.
• Electrochemical evaluation of OER performance in an alkaline medium, including overpotential and Tafel slope measurements.

Main Results:

• The (MnCoNiCuZn)O HEO exhibited favorable electronic conductivity.
• The HEO with equal cation concentrations showed the lowest overpotential (319 ± 5 mV @ 50 mA cm⁻²) and an optimal Tafel slope (78 ± 7 mV dec⁻¹).
• The material demonstrated sustained low overpotential at higher current densities.

Conclusions:

• The MOF-assisted synthesis provides an effective route for designing HEO electrocatalysts.
• Optimized cation concentration in HEOs significantly enhances OER performance.
• This study presents a promising design for HEO-based electrocatalysts for efficient and sustainable hydrogen and oxygen production.