Photoaccelerated Water Dissociation Across One-Atom-Thick Electrodes

Area of Science:

• Physical Chemistry
• Materials Science
• Electrochemistry

Background:

• Interfacial water dissociation (H₂O ⇆ H⁺ + OH⁻) is crucial for many chemical processes.
• Previous studies showed electric fields (Wien effect) accelerate this dissociation at graphene electrodes.
• Understanding ion dynamics at atomically thin interfaces is key for advanced applications.

Purpose of the Study:

• To investigate the effect of visible-light illumination on interfacial water dissociation at graphene.
• To explore the role of interfacial electric fields and graphene's proton selectivity in this photoeffect.
• To provide fundamental insights into light-enhanced ion dynamics at proton-selective interfaces.

Main Methods:

• Utilized one-atom-thick graphene as electrodes.
• Applied visible-light illumination to the graphene-water interface.
• Investigated interfacial electric fields and ion separation (protons and hydroxide ions).

Main Results:

• Achieved an order-of-magnitude acceleration of water dissociation under visible light.
• Observed spatial separation of protons and hydroxide ions across the graphene interface.
• Demonstrated enhancement of the process by strong interfacial electric fields.

Conclusions:

• Visible-light illumination significantly enhances interfacial water dissociation at graphene.
• The photoeffect is driven by graphene's proton selectivity and light-induced Wien effect acceleration.
• Findings suggest potential for photocatalysis and designing reconfigurable materials using strong interfacial fields.