Amphiphilic Bonding Intercalation Reshapes Active Sites and Interlayer Microenvironment for Selective and Stable...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Direct seawater electrolysis faces challenges due to the activity-durability trade-off and chloride corrosion.
• Layered double hydroxide (LDH) catalysts are promising but require improved stability and selectivity.

Purpose of the Study:

• To design corrosion-resistant and highly selective LDH catalysts for direct seawater electrolysis.
• To decouple catalyst activity from durability by engineering the catalyst's microenvironment.

Main Methods:

• Synthesized LDH catalysts using amphiphilic dodecylbenzenesulfonate (SDBS) to coordinate with Fe active centers.
• Employed density functional theory (DFT) and molecular dynamics (MD) simulations to investigate catalyst properties.
• Fabricated and tested NiFe-SDBS electrodes in a zero-gap anion exchange membrane (AEM) electrolyzer.

Main Results:

• The Fe-SDBS coordination formed robust Fe─O─S bonds, creating a stable microenvironment.
• DFT calculations showed enhanced Fe─O covalency and an upshifted Fe d-band center, lowering the oxygen evolution barrier.
• MD simulations revealed a reorganized interfacial hydrogen-bond network, creating a kinetic barrier against chloride ions (DOH-/DCl- ≈ 1.94).
• The NiFe-SDBS electrode achieved an ultralow overpotential (239 mV at 10 mA cm⁻²) and sustained high current densities (>1000 h at 1000 mA cm⁻²).
• In an AEM electrolyzer, the electrode reached 1000 mA cm⁻² at 4.64 kWh Nm⁻³ with excellent stability (>600 h at 500 mA cm⁻²).

Conclusions:

• Coordination-driven microenvironment engineering is a viable strategy for developing durable electrocatalysts.
• The developed NiFe-SDBS catalyst effectively addresses the limitations of seawater electrolysis, offering high activity and stability.
• This approach provides a generalizable paradigm for designing advanced catalysts for energy conversion applications.