Evaluation of the chemical reactions from two electrogenerated species in picoliter volumes by scanning electrochemical microscopy

Qian Wang, Joaquín Rodríguez-López, Allen J. Bard

Research output: Contribution to journalArticle

Abstract

The volume created by the positioning of two scanning electrochemical microscope (SECM) probes (tip and substrate) at a micrometric distance defines a "picoliter beaker" where homogeneous electron-transfer reactions are studied. The SECM is used to concurrently electrogenerate in situ two reactive species and to evaluate the possibility of detecting their reactivity. Two reaction cases are studied: the first, called the "reversible case", occurs when the electrochemically generated species at the substrate electrode can also react at the tip to yield the same product as the reaction in the gap. The second case, named the "irreversible case", occurs when the electrochemically generated species at the substrate are not able to react at the tip. Digital simulations are performed and compared to experimental studies. These show that an unusual compensation between collection and feedback effects render the analysis inapplicable in the "reversible case". The "irreversible case" is shown experimentally.

Original languageEnglish (US)
Pages (from-to)2969-2978
Number of pages10
JournalChemPhysChem
Volume11
Issue number13
DOIs
StatePublished - Sep 2010
Externally publishedYes

Keywords

  • Electrogeneration
  • Electron transfer
  • Feedback
  • Redox chemistry
  • Scanning electrochemical microscopy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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