Combining Scanning Electrochemical Microscopy with Infrared Attenuated Total Reflection Spectroscopy for in Situ Studies of Electrochemically Induced Processes

Abstract

The combination of scanning electrochemical microscopy (SECM) with single-bounce attenuated total reflection Fourier-transformed infrared spectroscopy (FT-IR-ATR) has been developed for in situ studies on electrochemically induced processes at IR waveguide surfaces via evanescent field absorption spectroscopy. The feasibility of the combined microelectrochemical FT-IR setup was demonstrated by spectroscopically monitoring microstructured polymer depositions induced via feedback mode SECM using a 25 mum Pt disk ultramicroelectrode (UME). The surface of a ZnSe ATR crystal was initially coated with 2,5-di-(2-thienyl)-pyrrole (SNS) layer, which was then locally polymerized during Ru(bpy)(3)(2+) mediated feedback mode SECM experiments. The polymerization reaction was simultaneously monitored by recording absorption intensity changes of SNS specific IR bands, thereby providing information on the polymerization mechanism and on the percentage of surface modification.

Invited Review Article: Combining scanning probe microscopy with optical spectroscopy for applications in biology and materials science

“…36,40 Scanning electrochemical microscopy has provided valuable insight in charge transfer mechanism at surfaces and electrochemical reactions. 37,43,44 For a more exhaustive list of feedback mechanisms recently developed to study individual atoms and molecules, the readers are encouraged to consult Ref. 45.…”

“…280 Using the same illumination geometry, a scanning electrochemical microscope (SECM) was combined with ATR-FTIR. 43,44 ATR-FTIR spectroscopy relies on the generation of an evanescent field on the waveguide surface, so it is extremely surfacesensitive and reduces the interferences with strong absorbers and water. The ATR crystal was an integral part of an electrochemical cell.…”

“…The combined SECM-ATR-FTIR was used to induce the electropolymerization of 2,5-di-(2-thienyl)-pyrrole by applying a potential to the microelectrode against a reference, and monitor the same reaction in situ with a time-lapse series of IR absorption spectra. 44 As for combinations of optical absorption spectroscopy and SPM, images of the optical absorption of individual carbon nanotubes were obtained with a sub-nanometer resolution using a combination of STM and illumination (total internal reflection) by a frequency-or amplitude-modulated laser. The STM tip measured variations of the tunneling current that were induced when the sample was in resonance.…”

Monitoring Scanning Electrochemical Microscopy Approach Curves with Mid-Infrared Spectroscopy: Toward a Novel Current-Independent Positioning Mode

“…A detailed description of the combined IR-ATR-SECM instrument is described elsewhere 1. In brief, broadband IR radiation from a FT-IR spectrometer (IRCube-M, Bruker Optics Inc., Billerica, MA) is externally collimated and focused onto the curvature of a single-bounce hemispherical ZnSe ATR crystal (3 mm in diameter, Harrick Scientific, Pleasantville, NY) by an off-axis parabolic mirror (OAP).…”

Dual microelectrodes decorated with nanotip arrays: Fabrication, characterization and spectroelectrochemical sensing

“…SECM has shown to be a very versatile technique pushing its limits towards new horizons: mapping the reactivity of various samples with better resolution, or with highly parallelized probes, or coupling the local electrochemical information with additional topographic and spectroscopic measurements [11][12][13][14][15][16][17]. This latter strategy has been pursued by several groups in recent years [18][19][20][21][22]. Indeed, the cross-correlation of spectroscopic information with local electrochemical measurements provides a powerful basis for increased selectivity and sensitivity.…”