Hybrid scanning electrochemical cell microscopy-interference reflection microscopy (SECCM-IRM): tracking phase formation on surfaces in small volumes

Valavanis, Dimitrios; Ciocci, Paolo; Meloni, Gabriel N.; Morris, Peter D.; Lemineur, Jean‐François; McPherson, Ian J.; Kanoufi, Frédéric; Unwin, Patrick R.

doi:10.1039/d1fd00063b

Cited by 60 publications

(75 citation statements)

References 96 publications

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“…Given a droplet radius of 25 nm, this current translates to a geometric j ORR value of −1273 mA cm –2 , 38-fold greater than the highest current densities observed under air using the GDE (Figure S25). The larger current densities observed in SECCM versus the GDE or RRDE configurations are consistent with the short diffusion pathways enforced by the nanoscopic dimensions of SECCM. ,,− …”

Section: Resultssupporting

confidence: 61%

Thousand-fold increase in O₂ electroreduction rates with conductive MOFs

et al. 2022

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Molecular materials must deliver high current densities to be competitive with traditional heterogeneous catalysts. Despite their high density of active sites, it has been unclear why the reported O 2 reduction reaction (ORR) activity of molecularly defined conductive metal−organic frameworks (MOFs) have been very low: ca. −1 mA cm −2 . Here, we use a combination of gas diffusion electrolyses and nanoelectrochemical measurements to lift multiscale O 2 transport limitations and show that the intrinsic electrocatalytic ORR activity of a model 2D conductive MOF, Ni 3 (HITP) 2 , has been underestimated by at least 3 orders of magnitude. When it is supported on a gas diffusion electrode (GDE), Ni 3 (HITP) 2 can deliver ORR activities >−150 mA cm −2 and gravimetric H 2 O 2 electrosynthesis rates exceeding or on par with those of prior heterogeneous electrocatalysts. Enforcing the fastest accessible mass transport rates using scanning electrochemical cell microscopy revealed that Ni 3 (HITP) 2 is capable of ORR current densities exceeding −1200 mA cm −2 and at least another 130-fold higher ORR mass activity than has been observed in GDEs. Our results directly implicate precise control over multiscale mass transport to achieve high-current-density electrocatalysis in molecular materials.

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Section: Resultssupporting

confidence: 61%

Thousand-fold increase in O₂ electroreduction rates with conductive MOFs

et al. 2022

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“…[28][29][30] Coupled with local electrochemical interrogation, e.g., a microsized electrolyte droplet confined on an electrode region, it allows visualizing a large set of (all) nanoobjects that are responsible of the electrochemical signature. [26,28,31,32] Such coupled methodology provides both the global electrochemical response of an ensemble of nanoobjects and the sum of all local individual nanoobjects. By bridging the gap between microscopic and macroscopic measurements, [12] it should provide a unique and complete (local to global [33] or single to ensemble) [34] identification and quantification of electrocatalytic phenomena at the nanoscale.…”

Section: Introductionmentioning

confidence: 99%

Bridging the Gap between Single Nanoparticle Imaging and Global Electrochemical Response by Correlative Microscopy Assisted By Machine Vision

et al. 2022

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The nanostructuration of an electrochemical interface dictates its micro‐ and macroscopic behavior. It is generally highly complex and often evolves under operating conditions. Electrochemistry at these nanostructurations can be imaged both operando and/or ex situ at the single nanoobject or nanoparticle (NP) level by diverse optical, electron, and local probe microscopy techniques. However, they only probe a tiny random fraction of interfaces that are by essence highly heterogeneous. Given the above background, correlative multimicroscopy strategy coupled to electrochemistry in a droplet cell provides a unique solution to gain mechanistic insights in electrocatalysis. To do so, a general machine‐vision methodology is depicted enabling the automated local identification of various physical and chemical descriptors of NPs (size, composition, activity) obtained from multiple complementary operando and ex situ microscopy imaging of the electrode. These multifarious microscopically probed descriptors for each and all individual NPs are used to reconstruct the global electrochemical response. Herein the methodology unveils the competing processes involved in the electrocatalysis of hydrogen evolution reaction at nickel based NPs, showing that Ni metal activity is comparable to that of platinum.

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“…Furthermore, we expect future possibilities for DAERI to synergize with other advanced characterization techniques, such as single-entity electrochemical techniques. Inspired by recent progress of single-entity electrochemistry, − DAERI may provide molecular structure information in both spatial and temporal dimensions combined with transient electrochemical processes of single cells, single particles, or single molecules at nanoconfined electrode interfaces. The diverse azo-type molecular designs and the high signal strength of azo-enhanced Raman probes can potentially relate single-entity electrochemical effects beyond the narrow enhancement zone of SERS obtained on noble metallic surfaces.…”

Section: Discussionmentioning

confidence: 99%

High-Resolution Low-Power Hyperspectral Line-Scan Imaging of Fast Cellular Dynamics Using Azo-Enhanced Raman Scattering Probes

Tang

Chu

et al. 2022

J. Am. Chem. Soc.

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Small-molecule Raman probes for cellular imaging have attracted great attention owing to their sharp peaks that are sensitive to environmental changes. The small cross section of molecular Raman scattering limits dynamic cellular Raman imaging to expensive and complex coherent approaches that acquire single-channel images and lose hyperspectral Raman information. We introduce a new method, dynamic azo-enhanced Raman imaging (DAERI), to couple the new class of azoenhanced Raman probes with a high-speed line-scan Raman imaging system. DAERI achieved high-resolution low-power imaging of fast cellular dynamics resolved at ∼270 nm along the confocal direction, 75 μW/μm 2 and 3.5 s/frame. Based on the azo-enhanced Raman probes with characteristic signals 10 2 −10 4 stronger than classic Raman labels, DAERI was not restricted to the cellular Raman-silent region as in prior work and enabled multiplex visualization of organelle motions and interactions. We anticipate DAERI to be a powerful tool for future studies in biophysics and cell biology.

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Hybrid scanning electrochemical cell microscopy-interference reflection microscopy (SECCM-IRM): tracking phase formation on surfaces in small volumes

Abstract: We describe the combination of scanning electrochemical cell microscopy (SECCM) and interference reflection microscopy (IRM) to produce a compelling technique for the study of interfacial processes and to track the...

Cited by 60 publications

References 96 publications

Thousand-fold increase in O₂ electroreduction rates with conductive MOFs

Thousand-fold increase in O₂ electroreduction rates with conductive MOFs

Bridging the Gap between Single Nanoparticle Imaging and Global Electrochemical Response by Correlative Microscopy Assisted By Machine Vision

High-Resolution Low-Power Hyperspectral Line-Scan Imaging of Fast Cellular Dynamics Using Azo-Enhanced Raman Scattering Probes

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Hybrid scanning electrochemical cell microscopy-interference reflection microscopy (SECCM-IRM): tracking phase formation on surfaces in small volumes

Abstract: We describe the combination of scanning electrochemical cell microscopy (SECCM) and interference reflection microscopy (IRM) to produce a compelling technique for the study of interfacial processes and to track the...

Cited by 60 publications

References 96 publications

Thousand-fold increase in O2 electroreduction rates with conductive MOFs

Thousand-fold increase in O2 electroreduction rates with conductive MOFs

Bridging the Gap between Single Nanoparticle Imaging and Global Electrochemical Response by Correlative Microscopy Assisted By Machine Vision

High-Resolution Low-Power Hyperspectral Line-Scan Imaging of Fast Cellular Dynamics Using Azo-Enhanced Raman Scattering Probes

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Product

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Thousand-fold increase in O₂ electroreduction rates with conductive MOFs

Thousand-fold increase in O₂ electroreduction rates with conductive MOFs