Electrochemical techniques for visualizing photoelectrochemical processes at the nanoscale

Tolbert, Chloe L.; McDonald, Declan M.; Hill, Caleb M.

doi:10.1016/j.coelec.2022.101164

Cited by 5 publications

(5 citation statements)

References 49 publications

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“…Scanning photoelectrochemical microscopy (SPECM) has been used to study micro-nanoscale photoactivities across samples surfaces, however photoelectrochemical contributions from features outside the intended scan areas leads to low resolution assessments of heterogeneity, and no capability for photocurrent density measurements. 90,91 By coupling SECCM with a light source, high sensitivity measurements of photocurrent densities confined to features residing within the probe area can be achieved. The constant tip-substrate separation also eliminates any influence of surface topography on the measured currents, particularly important for analysing photoelectrodes which are often highly nanostructured.…”

Section: Photoelectrochemistrymentioning

confidence: 99%

Five years of scanning electrochemical cell microscopy (SECCM): new insights and innovations

Gaudin,

Wright,

Harris-Lee

et al. 2024

Nanoscale

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Section: Photoelectrochemistrymentioning

confidence: 99%

Five years of scanning electrochemical cell microscopy (SECCM): new insights and innovations

Gaudin,

Wright,

Harris-Lee

et al. 2024

Nanoscale

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“…Monitoring electrochemical processes, including photoelectrochemical ones, on electrode surfaces in a spatiotemporally resolved manner is of high importance for both fundamental and applied research. This facilitates the exploration of various research aspects such as in situ assessment of local electrochemical interfaces and high-throughput screening of electrocatalysts. − Conventionally, electrochemical processes are monitored by measurements of electrical parameters (e.g., current, charge, and potential) averaged over the entire surface of electrodes. However, due to the inherent spatiotemporal heterogeneity of electrode surfaces, it is highly required to analyze electrochemical processes on electrode surfaces with spatial and temporal discrimination.…”

Section: Introductionmentioning

confidence: 99%

Flexible and Dynamic Light-Guided Electrochemiluminescence for Spatiotemporal Imaging of Photoelectrochemical Processes on Hematite

Han,

Lee,

Kim

et al. 2024

Anal. Chem.

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Here, we report an electrochemiluminescence (ECL)-based approach for imaging of local photoelectrochemical processes on hematite in a spatially and temporally controlled manner. The local processes were guided by flexible and dynamic light illumination, not requiring any prepatterned conductive features or photomasks, with a digital micromirror device (DMD). The imaging approach was based on light-addressable electrochemical reactions on hematite, resulting in photoinduced ECL emission for spatiotemporally resolved imaging of photoelectrochemical processes selectively guided by light illumination. After clarifying the capability of hematite as a photosensitive electrode, we validated that the illuminated hematite exhibited stable light-guided ECL emission in correspondence with the illuminated area, with a spatial resolution of 0.8 μm and a temporal resolution of 1 μs, even over a long period of 6 h. More importantly, this study exemplified the simple yet effective ECL-based approach for electrochemical visualization of local photoelectrochemical processes guided by flexible and dynamic adjustment of light illumination in a spatiotemporally controlled way.

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“…32 In this way, electrochemical measurements can therefore be performed at nanoscale locations within a confined area. 33 Scanning a grid of such measurements produces electrochemical maps and/or movies that can be compared with colocated structural or morphological information to reveal how local electrochemical properties relate to structure, for example, in catalytic thin films, 20,34 nanoparticles, 19,35 photoactive semiconductors, 36,37 battery materials, 38 and polycrystalline metals, in the context of catalysis 39 and corrosion. 40−42 To date, SECCM is most commonly used on relatively flat (nonporous) surfaces, where the area of surface residue left behind after each measurement (termed the meniscus or droplet "footprint") is representative of the working area of the electrochemical cell, and can be used to convert the measured currents to (geometric) current densities.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In this way, electrochemical measurements can therefore be performed at nanoscale locations within a confined area . Scanning a grid of such measurements produces electrochemical maps and/or movies that can be compared with colocated structural or morphological information to reveal how local electrochemical properties relate to structure, for example, in catalytic thin films, , nanoparticles, , photoactive semiconductors, , battery materials, and polycrystalline metals, in the context of catalysis and corrosion. − …”

Section: Introductionmentioning

confidence: 99%

Optimizing Amorphous Molybdenum Sulfide Thin Film Electrocatalysts: Trade-Off between Specific Activity and Microscopic Porosity

Harris-Lee,

Turvey,

Jayamaha

et al. 2024

ACS Appl. Mater. Interfaces

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Amorphous molybdenum sulfide (a-MoS x ) is a promising candidate to replace noble metals as electrocatalysts for the hydrogen evolution reaction (HER) in electrochemical water splitting. So far, understanding of the activity of a-MoS x in relation to its physical (e.g., porosity) and chemical (e.g., Mo/S bonding environments) properties has mostly been derived from bulk electrochemical measurements, which provide limited information about electrode materials that possess microscopic structural heterogeneities. To overcome this limitation, herein, scanning electrochemical cell microscopy (SECCM) has been deployed to characterize the microscopic electrochemical activity of a-MoS x thin films (ca. 200 nm thickness), which possess a significant three-dimensional structure (i.e., intrinsic porosity) when produced by electrodeposition. A novel two-step SECCM protocol is designed to quantitatively determine spatially resolved electrochemical activity and electrochemical surface area (ECSA) within a single, highthroughput measurement. It is shown for the first time that although the highest surface area (e.g., most porous) regions of the a-MoS x film possess the highest total activity (measured by the electrochemical current), they do not possess the highest specific activity (measured by the ECSA-normalized current density). Instead, the areas of highest specific activity are localized at/around circular structures, coined "pockmarks", which are tens to hundreds of micrometers in size and ubiquitous to a-MoS x films produced by electrodeposition. By coupling this technique with structural and elemental composition analysis techniques (scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy) and correlating ECSA with activity and specific activity across SECCM scans, this work furthers the understanding of structure−activity relations in a-MoS x and highlights the importance of local measurements for the systematic and rational design of thin film catalyst materials.

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Electrochemical techniques for visualizing photoelectrochemical processes at the nanoscale

Cited by 5 publications

References 49 publications

Five years of scanning electrochemical cell microscopy (SECCM): new insights and innovations

Five years of scanning electrochemical cell microscopy (SECCM): new insights and innovations

Flexible and Dynamic Light-Guided Electrochemiluminescence for Spatiotemporal Imaging of Photoelectrochemical Processes on Hematite

Optimizing Amorphous Molybdenum Sulfide Thin Film Electrocatalysts: Trade-Off between Specific Activity and Microscopic Porosity

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