How the colloid chemistry of precursor electrocatalyst dispersions is related to the polymer electrolyte membrane fuel cell performance

Bredol, Michael; Szydło, Aleksandra; Radev, Ivan; Philippi, Wladimir; Bartholomäus, Roland; Peinecke, Volker; Heinzel, Angelika

doi:10.1016/j.jpowsour.2018.09.005

Cited by 19 publications

(10 citation statements)

References 29 publications

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“…One major advantage of colloidal NCs is that they may be formulated as dispensable inks and therefore can be easily integrated into different device configurations, from RDE and H-cells to GDE-based cells. Generally, together with the overall device architecture, it is clear that the utilized deposition method and electrode preparation might also impact the performance of the catalytic system. ,,,− While the deposition should be performed in a way that the catalyst layer is as uniform as possible, intrinsic differences between various methods should also be taken into account, especially in the case of rough electrode surfaces. As a result, changing and comparing different deposition methods, which is feasible with NC inks, may serve as another way to tune the catalytic performance without changing the catalyst material or support itself.…”

Section: Discussionmentioning

confidence: 99%

Colloidal Nanocrystals as Electrocatalysts with Tunable Activity and Selectivity

et al. 2021

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Correlating the catalyst activity, selectivity, and stability with its structure and composition is of the utmost importance in advancing the knowledge of heterogeneous electrocatalytic processes for chemical energy conversion. Well-defined colloidal nanocrystals with tunable monodisperse size and uniform shapes are ideal platforms to investigate the effect of these parameters on the catalytic performance. In addition to translating the knowledge from single-crystal studies to more realistic conditions, the morphological and compositional complexity attainable by colloidal chemistry can provide access to active catalysts which cannot be produced by other synthetic approaches. The sample uniformity is also beneficial to investigate catalyst reconstruction processes via both ex situ and operando techniques. Finally, colloidal nanocrystals are obtained as inks, a feature which facilitates their integration on different substrates and cell configurations to study the impact of interactions at the mesoscale and the device-dependent reaction microenvironment on the catalytic outcome. In this Review, we discuss recent studies in selected electrochemical reactions and provide our outlook on future developments on the use of well-defined colloidal nanocrystals as an emerging class of electrocatalysts.

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Section: Discussionmentioning

confidence: 99%

Colloidal Nanocrystals as Electrocatalysts with Tunable Activity and Selectivity

et al. 2021

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“…The knowledge of its native dispersion state over time is important for the optimization of ink processing and consequent large-scale manufacturing of fuel cells. The size and concentration of particles, along with their interactions, affect macroscopic properties such as stability, , aggregation, , rheology, − and electrochemical performance. , However, ink formulation and processing is primarily governed by empiricism, and important process–structure–property relationships remain to be adequately explored. ,, …”

mentioning

confidence: 99%

Sedimentation Dynamics of Colloidal Formulations through Direct Visualization: Implications for Fuel Cell Catalyst Inks

Bapat

Segets

2020

ACS Appl. Nano Mater.

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Quantitative appraisal of real-world colloidal systems in their native state is key for knowledge-based nanoparticle formulations. Analytical centrifugation (AC) is touted as a quantitative methodology examining settling and creaming of dispersions, but an understanding of the main transmission readout is often nonintuitive and complex. Herein, we introduce a new visualization technique, called transmittograms, that readily depicts the time-resolved settling behavior of solid–liquid dispersions, measured by AC. We validate the utility of transmittogram analysis using silica particles. Further, we demonstrate the strength of the approach to study the nanoscale dynamics in complex fuel cell inks.

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“…Toward this end, several recipes for catalyst ink dispersions have been tuned for optimum kinetic and thermodynamic performance [9][10][11][12][13][14]. The cathode of a high-power density PEMFC is typically made of a catalyst ink consisting of carbon black (C), forming an extensive skeleton.…”

Section: Introductionmentioning

confidence: 99%

On the State and Stability of Fuel Cell Catalyst Inks

Bapat

Giehl²,

Kohsakowski³

et al. 2021

Preprint

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Catalyst layers (CL) as an active component of the catalyst coated membrane (CCM) form the heart of proton electrolyte membrane fuel cells (PEMFC). For optimum performance of the fuel cell, obtaining suitable structural and functional characteristics for the CL is crucial. Direct tuning of the microstructure and morphology of the CL is non-trivial; hence catalyst inks as catalyst layer precursors need to be modulated, which are then applied onto a membrane, to form the CCM. Obtaining favorable dispersion characteristics forms an important prerequisite in engineering catalyst inks for large scale manufacturing. In order to facilitate a knowledge-based approach for developing fuel cell inks, this work introduces new tools and methods to study both the dispersion state and stability characteristics, simultaneously. Catalyst inks were prepared using different processing methods which include stirring and ultrasonication. The proposed tools are used to characterize and elucidate the effects of the processing method. Structural characterization of the dispersed particles and their assemblages was carried out by means of transmission electron microscopy. Analytical centrifugation (AC) was used to study the state and stability of inks. Herein, we introduce new concepts, S score and stability trajectory, for a time-resolved assessment of inks in their native state using AC. The findings were validated and rationalized using transmittograms as a direct visualization technique. The flowability of inks was investigated by rheological measurements. It was found that probe sonication only up to an optimum amplitude leads to a highly stable colloidal ink.

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How the colloid chemistry of precursor electrocatalyst dispersions is related to the polymer electrolyte membrane fuel cell performance

Cited by 19 publications

References 29 publications

Colloidal Nanocrystals as Electrocatalysts with Tunable Activity and Selectivity

Colloidal Nanocrystals as Electrocatalysts with Tunable Activity and Selectivity

Sedimentation Dynamics of Colloidal Formulations through Direct Visualization: Implications for Fuel Cell Catalyst Inks

On the State and Stability of Fuel Cell Catalyst Inks

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