The new era of high throughput nanoelectrochemistry

Abstract

Scanning electrochemical probe microscopies (SEPMs) have played a key role in advancing small-scale electrochemistry. SEPMs use an electrochemical probe (micro/nanoelectrode or pipet) to quantify and map local interfacial fluxes of electroactive species and have found increasingly wide applications. Our contribution to the Fundamental and Applied Reviews in Analytical Chemistry 2019 discussed how advances in SEPMs converged towards nanoscale electrochemical mapping. This inflection in experimental capability has opened up myriad opportunities for SEPMs in many types of systems, from material and energy sciences to the life sciences. The enhancement in the spatial resolution of imaging techniques, and instrumental developments, have resulted in significant increases in the size of electrochemical datasets from a typical experiment and served to speed up measurement throughput. Next generation nanoelectrochemistry will thus see an emphasis on “big data”, its analysis, storage and curation, high throughput analysis and parallelization, “intelligent” instruments and experiments, active control of nanoscale systems, and the integration of nanoelectrochemistry and nanoscale micro(spectro)scopy. For this review article, we focus on recent advances in frontier nanoscale electrochemistry, analysis and imaging techniques that are already addressing some of these key targets, and are well-placed to embrace other aspects in the near future. Our goal is to provide an overview of the present state-of-the-art in high throughput nanoelectrochemistry and imaging, and signpost promising new avenues for nanoscale electrochemical methods.

Metal Core–Shell Nanoparticle Supercrystals: From Photoactivation of Hydrogen Evolution to Photocorrosion

“…In particular, the HER reaction is performed within an ≈10 3 μm 2 area of the surface, defined by a meniscus cell confined between a micropipet filled with the aqueous solution and the crystal-coated ITO substrate (see Figure 2a). This confinement technique, adapted from the scanning electrochemical cell microscope, [36,37] allows us to target optically multiple regions of interest (ROI) on the same substrate. [38,39] Note that a rather low H + concentration (10 mm) has been used to avoid damaging the ITO surface that has been shown to be unstable in too acidic conditions.…”

Key Requirements for Advancing Machine Learning Approaches in Single Entity Electrochemistry

“…Unlike macroscale electrochemical measurements that average responses across a bulk material, SEE reveals each entity's unique contributions, proving indispensable in applications like electrocatalysis, corrosion prevention, and sensor development. [7][8][9][10] SEE has seen significant advancements in the past decade, driven by developments in nanoscale scanning methods such as scanning electrochemical cell microscopy (SECCM), [10,11] scanning ion conductance microscopy (SICM), [10,12] and various optical techniques, [13,14] overcoming the challenges of nanoscale measurement. Some experts foresee the next pivotal development in SEE being facilitated by recent ML advancements yet SEE must evolve further for this prediction to materialize.…”

Next‐Generation Nanopore Sensors Based on Conductive Pulse Sensing for Enhanced Detection of Nanoparticles

“…However, characterizing nanoparticles in their native state, specifically in heterogeneous mixtures, presents many challenges. [5] Dynamic light scattering (DLS) or UV-vis spectroscopy are ensemble-averaging techniques and, therefore, fall short in fully characterizing heterogeneous nanoparticle mixtures. [6] Nanoparticle tracking analysis (NTA) is suitable for analyzing the size distribution of polydisperse nanoparticle suspensions with single entity resolution; however, the nanoparticles need to have a refractive index distinct from the surrounding medium or a fluorescent label is required.…”

“…[8] Nanopore sensing is a powerful label-free electrical technique that uses the Coulter principle for single-entity analysis. [5] In nanopore experiments, individual entities are driven through a nanopore under the influence of an electric field, causing a temporary modulation in the recorded ion current by a combination of geometrical exclusion of the electrolyte solution, ion concentration polarization, and additional charges brought by the analyte itself. [9,10] The magnitude and duration of these modulations reflect the translocation dynamics of the analyte, which are dependent on its physicochemical properties (e.g., size, shape, charge).…”