Quantitative Measurements of Electrocatalytic Reaction Rates with NanoSECM.
Anal Chem
; 96(15): 6089-6095, 2024 Apr 16.
Article
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| MEDLINE
| ID: mdl-38574269
ABSTRACT
Scanning electrochemical microscopy (SECM) has been extensively used for mapping electrocatalytic surface reactivity; however, most of the studies were carried out using micrometer-sized tips, and no quantitative kinetic experiments on the nanoscale have yet been reported to date. As the diffusion-limited current density at a nanometer-sized electrode is very high, an inner-sphere electron-transfer process occurring at a nanotip typically produces a kinetic current at any attainable overpotential. Here, we develop a theory for substrate generation/tip collection (SG/TC) and feedback modes of SECM with a kinetic tip current and use it to evaluate the rates of hydrogen and oxygen evolution reactions in a neutral aqueous solution from the current-distance curves. The possibility of using chemically modified nanotips for kinetic measurements is also demonstrated. The effect of the substrate size on the shape of the current-distance curves in SG/TC mode SECM experiments is discussed.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Anal Chem
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos