Nanoscale Electrochemistry Study Using SECCM Option of Park Systems

Abstract

Scanning electrochemical cell microscopy (SECCM) is a nanoelectrochemical scanning probe technique that creates a confined electrochemical cell (droplet) via meniscus contacting the surface by employing an electrolyte filled micropipette containing quasi-reference counter electrode(QRCE).[1] It is particularly useful to investigate the heterogeneity, or local electrochemical properties of the electrode surfaces by direct mapping the electroactivity with nanoscale resolution.In this study, the electrochemically reversible [Ru (NH3)6]3+/2+ electron transfer process at a highly ordered pyrolytic graphite (HOPG) surface was recorded using Park NX12 AFM system. A single barrel glass nanopipette with Ag/AgCl inserted as QRCE was utilized. Using previous successful experience in commercializing pipette-based electrochemical microscopy,[2] Park Systems’ hardware and software enables localized nanoscopic cyclic voltammetry measurements conducted at each pixel each time the meniscus contacts the surface. Thus, a spatially resolved surface electroactivity mapping of HOPG at various scan rates were created with high-throughput at the micro-/nanoscale. The difference in electrochemical activity measured at the edge plane relative to the basal plane surface was shown.This work demonstrates that Park Systems’ commercial SECCM option is promising for quantitative electroanalysis at the nanoscale, with potential applications in energy storage (battery) studies and corrosion research. [1] Gao, R., Edwards, M. A., Qiu, Y., Barman, K., & White, H. S. (2020). Visualization of Hydrogen Evolution at Individual Platinum Nanoparticles at a Buried Interface. Journal of the American Chemical Society. [2] Shi, W., Goo, D., Jung, G., Pascual, G., Kim, B., & Lee, K. Simultaneous Topographical and Electrochemical Mapping using Scanning Ion Conductance Microscopy–Scanning Electrochemical Microscopy (SICM-SECM). Figure 1