Electrochemistry
ITO electrodes are active everywhere at 50 nm
Open access · cc by · source: Europe PMC
Thousands of nanoscale voltammograms show every ITO patch oxidizes ferrocenedimethanol; only 0.2% is fully reversible, and the old sparse-site model fails.
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.
Key findings
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.
Methodology
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.
Limitations
The study uses one high-conductivity ITO grade and one outer-sphere couple; inner-sphere electrocatalysis maps are not reported.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
This library holds 17 empirical chemistry papers on electrochemistry with isolated findings, rates or spectra rather than reviews.
Evidence for the claim as stated.
Thousands of nanoscale voltammograms show every ITO patch oxidizes ferrocenedimethanol; only 0.2% is fully reversible, and the old sparse-site model fails.
Evidence for the claim as stated.
Faradaic efficiency and overpotential trade off; a high FE at impractical potential is not a working electrolyser.
Evidence for the claim as stated.
GSH-capped Ag uses SEM-EDX beside TEM diameters of 3.20, 4.83 and 6.19 nm (36/48/72 h) and SPR at 344–354 nm; gamma Ag/Se/Ag–Se particles average 10.95, 20.54 and 12.69 nm. Those papers are particle-sizing problems. A different indexed study maps ITO with a 50 nm SECCM pipette: the entire surface is active, only 0.2% of area is reversible (k⁰ ≥ 1 cm s⁻¹), 85.2% has mean k⁰ = 4.2×10⁻² cm s⁻¹, and a weighted average k⁰ ≈ 3.61×10⁻² cm s⁻¹ — activity, not an SEM micrograph.
Evidence for the claim as stated.
An SEM habit (nanoflowers versus pores) does not rank function. BiOBr nanoflowers coincide with 0.38 mA cm⁻² photocurrent but untreated Cl/I films fail stability despite also having SEM-visible nanostructure. Hydrogel SEM porosity coexists with 90.64% DEE that is a loading/release assay. SECCM at 50 nm further shows that a macroscale 'blocked' ITO reading is not a map of dead patches an SEM image would be asked to find.
Evidence for the claim as stated.
Nanoscale SECCM voltammetry can overturn a blocked-electrode reading of ITO. With a 50 nm pipette, every landing oxidised ferrocenedimethanol; only 0.2% of area was fully reversible (k⁰ ≥ 1 cm s⁻¹), 85.2% had mean k⁰ = 4.2×10⁻² cm s⁻¹, and a weighted average k⁰ ≈ 3.61×10⁻² cm s⁻¹. Film resistance, not inert patches, likely dominates the macroscale CV.
Evidence for the claim as stated.
Length scale and electrolyte change the ranking CV is allowed to report. ITO looks partly inert in macroscale CV and uniformly active at 50 nm; Pt OER facet order in PVP-containing pH 13.8 KOH is not the acidic single-crystal order. Quoting a k⁰ or a facet ranking without the length scale and wetting chemistry is the disagreement.
Evidence for the claim as stated.
This library holds 3 empirical chemistry papers on seccm with isolated findings, rates or spectra rather than reviews.
Evidence for the claim as stated.
Thousands of nanoscale voltammograms show every ITO patch oxidizes ferrocenedimethanol; only 0.2% is fully reversible, and the old sparse-site model fails.
Evidence for the claim as stated.
Droplet wetting and electrolyte composition change which sites you actually interrogate.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Faradaic efficiency and overpotential trade off; a high FE at impractical potential is not a working electrolyser.
- Supports · NaBH4 raises Ni3+ and speeds NiFe LDH OER
An SEM habit (nanoflowers versus pores) does not rank function. BiOBr nanoflowers coincide with 0.38 mA cm⁻² photocurrent but untreated Cl/I films fail stability despite also having SEM-visible nanostructure. Hydrogel SEM porosity coexists with 90.64% DEE that is a loading/release assay. SECCM at 50 nm further shows that a macroscale 'blocked' ITO reading is not a map of dead patches an SEM image would be asked to find.
Length scale and electrolyte change the ranking CV is allowed to report. ITO looks partly inert in macroscale CV and uniformly active at 50 nm; Pt OER facet order in PVP-containing pH 13.8 KOH is not the acidic single-crystal order. Quoting a k⁰ or a facet ranking without the length scale and wetting chemistry is the disagreement.
Droplet wetting and electrolyte composition change which sites you actually interrogate.
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Same topic cluster — not a recommendation engine.