ITO electrodes are active everywhere at 50 nm
Thousands of nanoscale voltammograms show every ITO patch oxidizes ferrocenedimethanol; only 0.2% is fully reversible, and the old sparse-site model fails.
Source
Nanoscale Visualization of Electrochemical Activity at Indium Tin Oxide Electrodes
Study at a glance
- Design
- Other — SECCM nanoscale LSV mapping of ITO with Butler–Volmer kinetic fitting
- N
- Thousands of landing sites on ITO — surface mapping, not a cohort N
- Population
- Indium tin oxide electrode surfaces
- Outcome
- Spatial distribution of heterogeneous electron-transfer rate constants
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Authors scanned ITO with a 50 nm SECCM nanopipette, recording FcDM0/+ LSVs at thousands of landings, then fit k0 and α with finite-element Butler–Volmer models and compared the map with macroscale CV.
What they found
The entire surface is active at ~50 nm resolution. 0.2% of area is reversible (k0 ≥ 1 cm s−1); 85.2% has mean k0 = 4.2×10−2 cm s−1; 14.6% is much slower (8×10−4 cm s−1). Weighted average k0 ≈ 3.61×10−2 cm s−1. Macroscopic “blocked electrode” interpretations overstate inert area; film resistance likely dominates macro kinetics.
The limits
What it doesn't show
The study uses one high-conductivity ITO grade and one outer-sphere couple; inner-sphere electrocatalysis maps are not reported.
Key terms
- SECCM
- Scanning electrochemical cell microscopy with a meniscus nanopipette cell.
- ITO
- Indium tin oxide, a transparent conducting oxide electrode.
- FcDM
- 1,1′-Ferrocenedimethanol, a fast outer-sphere redox probe.
- k0
- Standard heterogeneous electron-transfer rate constant.
- Blocked-electrode model
- Macro interpretation that only sparse 50–200 nm sites are active—rejected here.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
At 50 nm resolution ITO is:
Common questions
Is most of ITO inert?
No—the whole surface is active at 50 nm resolution.
How much is fully reversible?
About 0.2% of the area.
Typical k0?
Most sites ~4.2×10−2 cm s−1; average 3.61×10−2.
Why did macro CV look worse?
Likely lateral film resistance, not dead patches.
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