Fleeting-Active-Site-Thrust Oxygen Evolution Reaction by Iron Cations from the Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Oxygen evolution reaction (OER) is critical for sustainable energy technologies.
• Developing high-performance electrocatalysts requires understanding dynamic structure-performance relationships under working conditions.
• Ni-based layered double hydroxides (Ni-LDHs) are promising OER electrocatalysts.

Purpose of the Study:

• To uncover novel OER mechanisms driven by dynamic active sites.
• To elucidate the role of electrolyte components in electrocatalyst performance.
• To investigate the impact of fleeting active sites (FASs) on Ni-LDH OER activity and stability.

Main Methods:

• Grand-canonical ensemble simulations to study potential-dependent structures.
• Microkinetic modeling to elucidate reaction pathways.
• Operando analysis of Ni-LDHs under OER conditions.

Main Results:

• A new fleeting-active-site-thrust (FAST) mechanism was discovered, driven by Fe cations from the electrolyte forming dynamic FASs on Ni-LDHs.
• The FAST mechanism enhances OER activity via an intramolecular oxygen coupling pathway.
• Trace amounts (10-100 ppm) of FASs significantly boost and control OER performance, suppressing the lattice oxygen mechanism and improving stability.

Conclusions:

• The FAST mechanism is crucial for understanding and improving OER on Ni-LDHs.
• Electrolytes play a vital role in the structure-performance relationship of electrocatalysts.
• Engineering electrolytes offers an effective strategy for designing advanced OER electrocatalysts.