High-Speed Electrochemical Imaging

Abstract

The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm–2) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques.

Electrochemistry of Fe3+/2+ at highly oriented pyrolytic graphite (HOPG) electrodes: kinetics, identification of major electroactive sites and time effects on the response

“…25 ) on the basal plane is shown in Figure 9a, where a sigmoidal response for nonlinear (spherical segment) diffusion is observed, 49 due to the significantly enhanced mass transport in the tapered pipet, and under a bias applied between the barrels. 50,51 The value of potential difference between the 3/4 and 1/4-wave potentials (E 3/4 -E 1/4 ) was ~120 mV, and half-wave potential E 1/2 was shifted anodically by 397 mV from the formal potential, indicative of the irreversibility of CVs and slow ET kinetics of Fe 3+/2+ on HOPG. 49 The standard ET rate constant, k 0 , was found to be ~7.4×10 -5 cm s -1 , very close to that obtained from simulation of macroscopic CV measurements on the freshly cleaved surface, indicating that the SECCM measurements relate closely to a pristine surface (see ESI, † section S4).…”

Multifunctional scanning ion conductance microscopy

“…Constantdistance scanning is usually performed in a raster scan pattern [1,2,4,48], where line-by-line maps are generated, with a typical scan profile shown in figure 2b. More recently, a spiral scan profile has been introduced into SICM experiments [43,49], also depicted in figure 2b, greatly increasing image acquisition rates. In this configuration, the piezo positioners used to control the nanopipette (or sample) movement in the x-y plane are moving continuously.…”

Advances and Perspectives in Chemical Imaging in Cellular Environments Using Electrochemical Methods

“…Movies of electrochemical activity have been performed using LSV-SECCM for the hydrogen evolution reaction (HER) on MoS 2 to study the intrinsic activity of the edge and basal plane sites [127,128]. Unwin and coworkers [129] have implemented a non-raster-scan pattern following a spiral trajectory for faster imaging with SECCM. Image sequences were collected with a frame rate of 0.24 fps, meaning an image was recorded every 4 s. This is orders of magnitude higher than has been achieved before.…”