Hopping mode SECM imaging of redox activity in ionic liquid with glass-coated inlaid platinum nanoelectrodes prepared using a heating coil puller

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2018-04, Vol.815, p.231-237
• Main Authors: Jedraszko, Justyna, Michalak, Magdalena, Jönsson-Niedziolka, Martin, Nogala, Wojciech
• Format: Article
• Language: English
• Subjects: Aqueous electrolytes; Borosilicate glass; Capillary; Ductility; Electrochemical nanosensor; Electrodes; Electrolytes; Finite heterogeneous kinetics; Heat distributing units; Imaging; Ionic liquids; Malleability; Misalignment; Platinum; Regeneration; Scanning electron microscopy; Voltammetry
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2018.03.032

Major difficulties in nanoscale scanning electrochemical microscopy (SECM), resulting from the short tip-to-sample distance, are tilt misalignment and vertical thermal drift. This renders constant height mode nanoscale electrochemical imaging experimentally problematic. Nanoscale SECM also requires application of reliable nanoprobes. Although SECM nanotips are commercially available, they are rather disposable, fragile and their shelf-life is limited. Many SECM laboratories employ self-prepared nanoprobes, fabricated using advanced apparatus. In this paper, we employ a hopping mode approach to nanoscale electrochemical imaging, which resolves the mentioned common difficulties. The applied platinum nanoelectrodes, insulated with borosilicate glass, were prepared using affordable equipment and materials. They were applied for nanoscale mapping of redox mediator regeneration at a model interdigitated microsensor, composed of Pt microband electrodes, in a solution of ferrocene in viscous hydrophobic room temperature ionic liquid (RTIL) – 1-butyl-3-methylimidazoliumbis(trifluoro-methylsulfonyl)imide (C4mim N(Tf)2). The presented nanosensors were also characterized with cyclic voltammetry in aqueous electrolyte containing hexamineruthenium (III) chloride as redox mediator. [Display omitted] •Nanoscale electrochemical activity imaging in ionic liquid•Hopping mode scanning electrochemical microscopy•Preparation of SECM nanotips