High-Throughput Correlative Electrochemistry–Microscopy at a Transmission Electron Microscopy Grid Electrode

Abstract

As part of the revolution in electrochemical nanoscience, there is growing interest in using electrochemistry to create nanostructured materials and to assess properties at the nanoscale. Herein, we present a platform that combines scanning electrochemical cell microscopy with ex situ scanning transmission electron microscopy to allow the ready creation of an array of nanostructures coupled with atomic-scale analysis. As an illustrative example, we explore the electrodeposition of Pt at carbon-coated transmission electron microscopy (TEM) grid supports, where in a single high-throughput experiment it is shown that Pt nanoparticle (PtNP) density increases and size polydispersity decreases with increasing overpotential (i.e., driving force). Furthermore, the coexistence of a range of nanostructures, from single atoms to aggregates of crystalline PtNPs, during the early stages of electrochemical nucleation and growth supports a nonclassical aggregative growth mechanism. Beyond this exemplary system, the presented correlative electrochemistry–microscopy approach is generally applicable to solve ubiquitous structure–function problems in electrochemical science and beyond, positioning it as a powerful platform for the rational design of functional nanomaterials.

Synchronous Electrical Conductance‐ and Electron Tunnelling‐Scanning Electrochemical Microscopy Measurements

“…Electrodeposition was performed using a two‐electrode setup with the carbon nanoelectrode as the working electrode and an AgCl‐coated Ag wire acting as a quasi‐reference counter electrode (QRCE). Cyclic voltammetry (CV) measurements (scan rate of 0.2 V s −1 ensuring close to steady‐state conditions at the nanoscale) between 0.3 V and −0.2 V in an aqueous solution containing 1 mM H 2 PtCl 6 ⋅ 6H 2 O (Sigma‐Aldrich) and 0.1 M HClO 4 (70 %, Sigma‐Aldrich) were performed repetitively until the measured current at the −0.2 V end of the sweep (enough for the reduction of platinum) exceeded 50 pA (Supporting Information, Figure S2a). In general, the aim was to produce a corresponding increase by a factor of ca.…”

Nanoscale electrochemistry in a copper/aqueous/oil three-phase system: surface structure–activity-corrosion potential relationships

“…When an O 2 -free environment was needed, an environmental cell was used, through which Argon was flowed for at least an hour before and during experiments, as outlined in previously. 32,46 The SECCM experiments were performed in the chronopotentiometric mode, with a "hopping mode" imaging protocol, employing a home-built sensitive galvanostat with an ultralow input bias current, as previously described. 40 The procedure consisted of approaching the nanopipette probe to the surface in a series of predefined points of a rectangular grid.…”

Electrochemistry and Optical Microscopy

“…It is illusory to seek for absolute optical measurement. One would rather evaluate relative variations of a quantity (mass, volume, etc…) from optical intensity variations and resort to calibration procedures to verify the predicted trends, using different molecular probes or NP gauges, and cross-correlating the optical images with multiple microscopic observations [75][76][77][78]. Resolution is the ability of an imaging tool to distinguish (resolve) in an image two objects.…”