Manipulating Intermetallic Charge Transfer for Switchable External Stimulus-Enhanced Water Oxidation Electrocatalysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Oxygen evolution reaction (OER) is crucial for energy conversion but kinetically limited by intermediate scaling relationships.
• Optimizing OER electrocatalysts is essential for efficient energy technologies.
• Prussian blue analogues offer tunable electronic properties for catalysis.

Purpose of the Study:

• To investigate methods for breaking scaling relationships in OER.
• To enhance the electrocatalytic activity of Co-Fe Prussian blue electrodes using external stimuli.
• To explore stimuli-responsive OER mechanisms.

Main Methods:

• Electrochemical measurements of Co-Fe Prussian blue modified electrodes.
• Application of external stimuli: magnetic field (0.2 T) and light irradiation (100 mW cm⁻²).
• Density Functional Theory (DFT) simulations to understand reaction mechanisms and electronic structure.

Main Results:

• Significant OER activity enhancements of ~11% (magnetic field) and ~57% (light irradiation) at η=0.6 V, pH 7.
• Correlation between enhanced activity and intermetallic charge transfer (IMCT) intensity between Fe and Co sites.
• DFT simulations indicate a shift to a spin crossover-based OER pathway under stimuli.

Conclusions:

• External stimuli can effectively overcome OER scaling limitations.
• Tuning IMCT is key to enhancing electrocatalytic performance.
• The study demonstrates the potential for switchable electrocatalytic devices based on stimuli-responsive mechanisms.