title: Use of catechol as selective redox mediator in scanning electrochemical microscopy investigations.
abstract: The use of catechols, and more specifically of dopamine, as a specific redox mediator for scanning electrochemical microscopy (SECM) investigations was evaluated in the challenging situation of an ultrathin layer deposited on a conductive substrate (carbon materials). Experiments show that dopamine is a well-adapted redox system for SECM in feedback mode and in unbiased conditions. Used as a redox mediator, catechol permits the investigations of modified surfaces without an electrical connection of the sample thanks to fast charge transfer kinetics but with a surface selectivity that does not exist in classical outer-sphere redox mediators. The interest of catechol in SECM as a sensitive redox mediator is exemplified by monitoring several modification steps of an ultrathin (<1 nm) hierarchically porous organic monolayer deposited on carbon substrates. For quantitative analysis, the SECM approach curves using dopamine could simply be characterized with an irreversible electron transfer kinetics model in a large range of pH.
authors: Institut des Sciences Chimiques de Rennes, Université de Rennes 1, CNRS, UMR 6226 (Equipe MaCSE), Rennes, France.
authors: Sebastien
authors: S
authors: Lhenry
authors: Yann R
authors: YR
authors: Leroux
authors: Philippe
authors: P
authors: Hapiot
mesh_terms: D000480:Alkynes / Q000737:chemistry; D001386:Azides / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D004298:Dopamine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D016062:Porosity
chemical_list: D000480:Alkynes; D001386:Azides; D002396:Catechols; D002244:Carbon; C034221:catechol; D004298:Dopamine