Push-Pull Electronic Effects in Surface-Active Sites Enhance Electrocatalytic Oxygen Evolution on Transition Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Sustainable electrocatalysis of the oxygen evolution reaction (OER) is vital for green fuel production.
• Nickel and iron oxides are promising OER catalysts in alkaline media, but their ill-defined structures hinder understanding.
• Identifying key descriptors for efficient OER electrocatalysts remains a significant challenge.

Purpose of the Study:

• To investigate Fe-Ni-Zn spinel oxides with well-defined crystal structures as a platform for understanding OER mechanisms.
• To elucidate the role of specific structural and electronic properties in optimizing OER performance.
• To identify key contributions and design principles for advanced OER electrocatalysts.

Main Methods:

• Synthesis and characterization of Fe-Ni-Zn spinel oxides with controlled stoichiometry.
• Electrochemical evaluation of OER performance in alkaline media.
• Analysis of surface structure, electronic properties, and active site contributions.

Main Results:

• Maximum OER performance was achieved with the presence of zinc in the spinel structure.
• Dense, equimolar 1:1:1 stoichiometry sites on the surface were found to be critical for high activity.
• These sites facilitate oxygen vacancy formation, where zinc promotes electronic density, lowering overpotential.

Conclusions:

• Cooperative electronic effects on surface active sites are key to designing optimal OER electrocatalysts.
• Fe-Ni-Zn spinel oxides offer a tunable platform for understanding and enhancing OER catalysis.
• The findings provide a general understanding of structure-performance relationships for sustainable OER.