Scanning Electrochemical Microscopy

Scanning electrochemical microscopy (SECM) is a scanning probe technique in which an ultramicroelectrode (UME) is poised in close proximity to another electrode’s surface to obtain information about its reactivity—such as through feedback of a redox mediator in solution between the UME and surface (Figure 1)—or to modify the surface. The UME is attached to highly sensitive motors that can adjust the distance of the UME from the surface or move it laterally to obtain an image of the topography and/or reactivity of the surface. Our SECM system from CH Instruments (Figure 2) is used to probe the activity of electrode surfaces, such as graphene and photocatalysts.Our group has also combined SECM capabilities with in situ mass spectrometry for characterizing electrocatalysts.

Figure 1. Diagram of SECM cell and redox mediator feedback between the SECM tip and surface.

Figure 1. Diagram of SECM cell and redox mediator feedback between the SECM tip and surface.

Figure 2. Picture of the Model 900 CH Instruments SECM in our group.

Figure 2. Picture of the Model 900 CH Instruments SECM in our group.

Citations

  1. N. L. Ritzert, J. Rodríguez-López, C. Tan, and H. D. Abruña. Kinetics of Interfacial Electron Transfer at Single Layer Graphene Electrodes in Aqueous and Non-Aqueous Solutions. Langmuir 2013, 29, 1683-1694.
  2. E. D. Rus, H. Wang, A. E. Legard, N. L. Ritzert, R. B. Van Dover, and H. D. Abruña. An Exchangeable-Tip Scanning Probe Instrument for the Analysis of Combinatorial Libraries of Electrocatalysts. Rev.Sci. Instrum. 2013, 84,024101.
  3. J. Rodríguez-López, N. L. Ritzert, J. A. Mann, C. Tan, W. R. Dichtel, and H. D. Abruña. Quantification of the Surface Diffusion of Tripodal Binding Motifs on Graphene using Scanning Electrochemical Microscopy. J. Am. Chem. Soc. 2012, 134, 6224-6236.
  4. C. Tan, J. Rodríguez-López, J. J. Parks, N. L. Ritzert, D. C. Ralph, and H. D. Abruña. Reactivity of Monolayer Chemical Vapor Deposited Graphene Imperfections Studied using Scanning Electrochemical Microscopy. ACS Nano 2012, 6, 3070-3079.