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

Abstract

Probing Cu corrosion in an aqueous nanodroplet/oil/metal three-phase environment revealed unique patterns of surface reactivity. The electrochemistry of high-index facets cannot be predicted simply from the low-index {001}, {011} and {111} responses.

Screening Surface Structure–Electrochemical Activity Relationships of Copper Electrodes under CO2 Electroreduction Conditions

“…Full details of the method development and calculation are published elsewhere. 32 Data from Figure 2 A are plotted in Figure 3 , according to the surface crystallography, with the low-index grains in the face-centered cubic (fcc) crystal system, (100), (110), and (111), discussed in the previous section, shown, respectively, in red, green, and blue in the corners of the plot. The average Euler angles, hkl index, coordinates on the two-dimensional projection, electroreduction current density, and number of linear sweep voltammograms collected on each grain with SECCM are detailed in Supporting Information , Section S4, Table S1.…”

“…In this way, electrochemical analysis of multiple crystallographic orientations and grain boundaries, found on a polycrystalline metal surface, is achieved 30 , 31 as demonstrated by studies of an increasing diversity of systems. 24 , 28 , 32 − 38 Recent studies have used the combination of SECCM and EBSD to resolve CO 2 electroreduction activity at grain boundaries of Au, 39 − 41 and SECCM alone has been used to study CO 2 electroreduction at tin/reduced graphene oxide interfaces. 42 …”

“…The considerable amount of data acquired with SECCM (up to 2500 LSVs over about 60 different grains in a single map) enabled the construction of “electrochemical stereographic triangles” 32 in which electrocatalytic activity of individual grains is presented with respect to their crystallographic orientations, on a 2D projection which is qualitatively similar to an inverse pole figure (IPF) representation, thereby offering a holistic view of structure–activity that reveals insightful trends across the low-index grains and many high-index crystallographic orientations. This study serves to demonstrate the use of pseudo-single crystal SECCM–EBSD for screening and identifying promising surface features on an electrocatalyst for further investigation.…”

Zooming‐in – Visualization of active site heterogeneity in high entropy alloy electrocatalysts using scanning electrochemical cell microscopy

“…This configuration enhances mass transport of gaseous reagents to reactive sites and facilitates product exchange with the surrounding environment enabling the study of reactions requiring a gaseous reactant. [30,[34][35][36] For the ORR under SECCM conditions, previous studies reveal that whereas O 2 transport is provided down the barrels of the pipette as well as across the electrolyte-air interface, solution-phase reactants and products such as H + and H 2 O 2 , can only diffuse to and from the sample through the barrel of the pipette and as such the depleted proton concentration at the electrode surface and hence shift of the local pH value decreases the effectively applied overpotential at the electrode-electrolyte interface. [37] This mismatch between oxygen and proton transport pathways is peculiar to that of proton exchange membrane fuel cells.…”

Calibrating SECCM measurements by means of a nanoelectrode ruler. The intrinsic oxygen reduction activity of PtNi catalyst nanoparticles

“…Hence, SECCM with gaseous educts or products is mimicking to a certain extent a gas diffusion electrode by creating a 3-phase gas/electrolyte/catalyst boundary [38]. The SECCM technique has been constantly refined since its introduction in order to allow its use in special applications such as non-aqueous electrolytes [39], photo-electrochemistry [40], and oil-coated substrates [41,42].…”