Flexible open-source nanoscale electrochemical microscopy.

by Edwards, Martin Andrew; McKelvey, Kim; Kang, Minkyung; Brunet Cabre, Marc; Jones, Nicholas Brenton; Unwin, Patrick R.

Electrocatalytic reactions underpin numerous scientifically and industrially important processes and technologies, e.g., fuel cells, electrochem. syntheses, CO2 redn. These reactions take place at the surface of electrodes which are heterogeneous in nature, e.g., nanoparticles on carbon supports, grain and phase boundaries, etc.; even model single crystal surfaces contain defect sites. Heterogeneous electrodes have spatially heterogenous electrochem. behaviors. To gain deep understanding of processes on electrode surfaces requires a spatially-resolved view, which allows one to answer fundamental questions, such as 'do all nanoparticles show equal electrochem. activity". Classical electrochem. methods characterize electrodes by elec. connecting them, immersing them in electrolyte, and measuring the current or voltage response. This quantifies the response of the entire electrode, averaging out responses of the individual surface components. Scanned electrochem. probe microscopy employs mobile nanoelectrodes and nanopipettes as probes to measure the current/voltage response in small portions of the electrode surface (~10 nm to ~1 µm). Repeating measurements in a raster pattern creates maps of the electrochem. characteristics of electrode surfaces, allowing assessment of heterogeneity and the behavior of individual components. Scanned electrochem. probe microscopy has grown significantly over the past decades. However, it is still predominantly restricted to specialized labs. A key barrier is instrumentation, which requires expertise and resources for programming control software and fabrication of custom components. In this talk I will introduce our flexible open-source scanning electrochem. probe microscope. I will explain how the software allows implementation of common protocols with no programming and custom experimentation with only minimal expertise. I will explain freely available 3D designs allow custom phys. components to fabricated, even without local access to fabrication instrumentation/expertise. By making this instrument freely available, we hope that to encourage the uptake of electrochem. microscopy to be applied to the widest range of technol. and scientifically important systems.