Cations induced in situ electrochemical amorphization for enhanced oxygen evolution reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Surface reconstruction is common in transition metal catalysts during operando oxygen evolution reactions (OER).
• Optimizing this reconstruction is crucial for high electrochemical active surface area and reaction kinetics but remains challenging.

Purpose of the Study:

• To investigate electrolyte engineering as a strategy to control surface reconstruction in Fe2O3 catalysts under OER conditions.
• To understand how electrolyte additives influence the crystalline-to-amorphous structural conversion and its impact on catalytic performance.

Main Methods:

• Operando oxygen evolution reaction (OER) studies on Fe2O3 catalysts.
• Electrolyte engineering by intentionally adding cations (e.g., Co2+).
• Spectroscopic measurements and density functional theory (DFT) calculations to analyze structural and electronic properties.

Main Results:

• Added cations in the electrolyte facilitated a crystalline-to-amorphous structure conversion on the Fe2O3 surface.
• The amorphous structure provides abundant, well-defined active sites, enhancing electron transfer, mass transport, and intermediate adsorption.
• Co2+ assistant resulted in a 17.9% enhancement in current density at 2.32 V (vs. RHE).

Conclusions:

• Electrolyte engineering is a viable strategy to regulate catalyst reconstruction during OER.
• The study provides a generalized in-situ method for designing advanced catalysts by controlling surface structure.
• Amorphous surface structures are beneficial for improving catalytic activity in OER.