Cocatalysis: Role of Organic Cations in Oxygen Evolution Reaction on Oxide Electrodes

Zoric, Marija R.; Kadel, Usha Pandey; Glusac, Ksenija D.

doi:10.1021/acsami.8b10232

Cited by 6 publications

(8 citation statements)

References 30 publications

(69 reference statements)

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“…Based on the Pourbaix diagrams, the authors identify anionic intermediate 2 as the key intermediate activating molecular oxygen towards reduction to hydroperoxide 3. Reactive sites are identified as carbon atoms adjacent to nitrogen atoms, which is in a good agreement with ORR studies on analogous metal-free models [80][81][82][83] . Subsequent computational investigation of the catalytic cycle 84 identified an unusual ether-like structure 4 as an intermediate, that ensures the four-electron pathway.…”

Section: Insights From Molecular Modelssupporting

confidence: 82%

Toward a mechanistic understanding of electrocatalytic nanocarbon

Askins

Zoric

et al. 2021

Nat Commun

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Electrocatalytic nanocarbon (EN) is a class of material receiving intense interest as a potential replacement for expensive, metal-based electrocatalysts for energy conversion and chemical production applications. The further development of EN will require an intricate knowledge of its catalytic behaviors, however, the true nature of their electrocatalytic activity remains elusive. This review highlights work that contributed valuable knowledge in the elucidation of EN catalytic mechanisms. Experimental evidence from spectroscopic studies and well-defined molecular models, along with the survey of computational studies, is summarized to document our current mechanistic understanding of EN-catalyzed oxygen, carbon dioxide and nitrogen electrochemistry. We hope this review will inspire future development of synthetic methods and in situ spectroscopic tools to make and study well-defined EN structures.

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Section: Insights From Molecular Modelssupporting

confidence: 82%

Toward a mechanistic understanding of electrocatalytic nanocarbon

Askins

Zoric

et al. 2021

Nat Commun

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“…Though COFs and their metallated analogues have recently been investigated for WOR and HER, [31–35] hydrogen‐bonded systems have remained largely unexplored. There is a huge untapped potential in the designing of hydrogen‐bonded organic materials by incorporating desired functionalities, which are expected to facilitate WOR [36,37] . The proof‐of‐concept for the applicability of organic ionic systems in water electrolysis was provided by Glusac and co‐workers in their seminal exploration of flavinium derivatives [36] .…”

Section: Introductionmentioning

confidence: 99%

Melamine‐Based Hydrogen‐bonded Systems as Organoelectrocatalysts for Water Oxidation Reaction

et al. 2023

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Applications of small organic molecules and hydrogen-bonded aggregates, instead of traditional transition-metal-based electrocatalysts, are gaining momentum for addressing the issue of low-cost generation of H 2 to power a sustainable environment. Such systems offer the possibility to integrate desired functional moieties with predictive structural repetition for modulating their properties. Despite these advantages, hydrogen-bonded organic systems have largely remained unexplored, especially as electrocatalysts. Melamine and adipic acid-based hydrogenbonded organic ionic (BMA) and co-crystal systems developed under varying temperatures are explored as electrocatalysts for water oxidation reaction (WOR). These systems are easily modifiable with precisely designed molecular architecture and judiciously positioned nitrogen atoms. Combined effect of charge-assisted hydrogen bonding stabilizes the ionic BMA system under corrosive alkaline conditions and augments its remarkable electrocatalytic WOR activity, achieving a current density of 10 mA cm À 2 at an overpotential of 387 mV and Faradaic efficiency ~94.5 %. The enhanced electrocatalytic ability of BMA is attributed to its hydrophilic nature, unique molecular composition with complementary hydrogen-bonded motifs and a high density of positively charged nitrogen atoms on the surface, that facilitates electrostatic interactions and accelerate charge and mass transport processes culminating in a turnover frequency of ~0.024 s À 1 . This work validates the potential of hydrogen-bonded molecular organo-electrocatalysts towards WOR.

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“…For example, most of the discharge mediators are quinone-based and the large number of compounds from this family, with electron withdrawing and donating groups, have already been explored. Following our group's interest in redox-active organic compounds as catalysts and co-catalysts in electrochemistry [43][44][45][46][47][48][49][50][51][52][53] , we investigate here a new type of discharge mediator for Li-O2 batteries, based on triarylmethyl cation motifs (Scheme 1a). Computational screening at the density functional theory (DFT) level was used to evaluate the thermodynamic parameters that control the inner-sphere and outersphere catalysis mechanisms for the O2/Li2O2 reduction by the triarylmethyl cations under study.…”

Section: Introductionmentioning

confidence: 99%

Li-O2 Battery Discharge Redox Mediation by Triarylmethyl Cations

Askins

Zoric

Amine

et al. 2022

Preprint

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Low discharge capacities resulting from electronically insulating Li2O2 film growth on carbon electrodes is a major impediment to Li-O2 battery commercialization. Redox mediation is an effective strategy to drive oxygen chemistry into solution, avoiding surface-mediated Li2O2 film growth and extending discharge lifetimes. However, to continue improving upon prior research, exploration of new classes of redox mediators and discovery of novel selection criteria is required. Herein, we report a new class of triarylmethyl cations which are effective at enhancing discharge capacities up to 26-fold. Surprisingly, we observe that redox mediators with more positive redox mediator reduction potentials, and thus more sluggish kinetics for reaction with oxygen, lead to larger discharge capacities because of their improved ability to suppress the surface-mediated reduction pathway. This result provides important structure- property relationships for future improvements in redox-mediated O2/Li2O2 discharge capacities. To aid future redox mediator discovery, we applied a chronopotentiometry model to investigate the zones of redox mediator standard reduction potentials and concentrations needed to achieve efficient redox mediation at a given current density. This analysis is expected to guide future redox mediator exploration.

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Cocatalysis: Role of Organic Cations in Oxygen Evolution Reaction on Oxide Electrodes

Cited by 6 publications

References 30 publications

Toward a mechanistic understanding of electrocatalytic nanocarbon

Toward a mechanistic understanding of electrocatalytic nanocarbon

Melamine‐Based Hydrogen‐bonded Systems as Organoelectrocatalysts for Water Oxidation Reaction

Li-O2 Battery Discharge Redox Mediation by Triarylmethyl Cations

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