Unveiling the Angstrom-Scale Interfacial Electron Spillover through the Metal/Electrolyte Interface.

Area of Science:

• Electrochemistry
• Surface Science
• Spectroscopy

Background:

• Understanding solid-liquid interfacial electron spillovers is key for heterogeneous reactions and catalysis.
• Current knowledge of interfacial electron spillovers lacks angstrom-scale experimental detail, remaining largely conceptual.

Purpose of the Study:

• To experimentally demonstrate and quantify interfacial electron spillover at electrode-electrolyte interfaces with angstrom-scale resolution.
• To correlate electron spillover to molecular responses using a plasmonic molecular ruler strategy.

Main Methods:

• Combined in situ electrochemical plasmon-enhanced Raman spectroscopy (PERS) with a plasmonic molecular ruler strategy.
• Utilized molecules adsorbed on metallic electrodes (Pt, Pd, Au, Ag) as molecular rulers to probe electron spillover.
• Correlated PERS band shifts of functional groups to electron spillover, achieving angstrom-scale spatial resolution.

Main Results:

• Successfully demonstrated and quantified interfacial electron spillover at electrode-electrolyte interfaces.
• Observed electron spillover lengths up to 4 Å at the Ag electrode-organic electrolyte interface.
• Found electron spillover length to be highly dependent on applied potentials, electrode metals, and electrolyte composition.

Conclusions:

• Provided the first quantitative measurements of angstrom-scale electronic behaviors at metal-liquid interfaces.
• The findings offer guidance for tailoring metal properties under electrochemical polarization.
• Opens possibilities for active control of quantum plasmonics for angstrom-scale interfacial sensing.