Electrochemical oxidation of ordered mesoporous carbons and the influence of graphitization

Pérez-Rodríguez, S.; Sebastián, David; Lázaro, M.J.

doi:10.1016/j.electacta.2019.02.065

Cited by 30 publications

(26 citation statements)

References 61 publications

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“…40 Graphitized carbons (gOMC-R2 and gOMC-R5) were obtained by heat treatment at 1500 ºC of the as-synthesized OMC for 1 h under Ar flow. 34,40 These graphitization conditions enhance the formation of a crystalline carbon framework without a significant impact on the mesoporous structure of OMC. 33,34 Electrooxidation tests.…”

Section: Methodsmentioning

confidence: 99%

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Insights on the Electrochemical Oxidation of Ordered Mesoporous Carbons

Pérez-Rodríguez

Sebastián

Lázaro

2020

J. Electrochem. Soc.

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Ordered mesoporous carbon materials (OMC) present a developed porosity, making them promising candidates for electrochemical energy-conversion devices. However, OMC undergo electrochemical oxidation causing the degradation of electrodes and exhibit low electrical conductivities due to their amorphous carbon structure. To address these issues, OMC can be graphitized by thermal treatments. Herein, the electrooxidation behaviour of different OMC, prior and upon graphitization, is studied by chronoamperometry in a highly acidic electrolyte (0.5 M H2SO4). Several oxidation potentials and temperatures are used to gain insights on the electrooxidation mechanism. Potential holding tests evidenced differences in the oxidation behaviour of as-synthesized and graphitized materials. Graphitization results in a strong decrease of the oxidation charge from 93 to 7% depending on the carbon properties, applied potential and temperature. Temperature plays an important role on carbon degradation of not-graphitized OMC, with a strong electrochemical capacitance loss (90-93%) after tests at 40 and 60 ºC. Conversely, graphitized materials present a raise of the capacitance by the creation of oxygenfunctionalities as confirmed by post-mortem X-ray photoelectron spectra analysis. Additionally, graphitized materials show an increase of the apparent activation energy associated to electrooxidation (7 times higher), indicative of their improved resistance.

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Section: Methodsmentioning

confidence: 99%

“…A Gaussian (40%)/Lorentzian (60%) fitting was used for all the contributions, with the exception of the Csp 2 , where an asymmetric peak shape was employed. 40,45,46…”

Section: Methodsmentioning

confidence: 99%

Insights on the Electrochemical Oxidation of Ordered Mesoporous Carbons

Pérez-Rodríguez

Sebastián

Lázaro

2020

J. Electrochem. Soc.

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“…As-synthesized ordered mesoporous carbons (SBA-15 silica as a template and a furan resin/acetone mixture as carbon precursor) were subjected to further modifications to enhance the formation of a crystalline carbon framework while maintaining the mesoporous structure. To meet the goal, ordered mesoporous carbons were graphitized at 1500 °C for 1 h under continuous Ar flow [ 75 , 76 ].…”

Section: Synthesis Of Carbon-based Nanocompositesmentioning

confidence: 99%

Carbon-Based Composites as Electrocatalysts for Oxygen Evolution Reaction in Alkaline Media

et al. 2021

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This review paper presents the most recent research progress on carbon-based composite electrocatalysts for the oxygen evolution reaction (OER), which are of interest for application in low temperature water electrolyzers for hydrogen production. The reviewed materials are primarily investigated as active and stable replacements aimed at lowering the cost of the metal electrocatalysts in liquid alkaline electrolyzers as well as potential electrocatalysts for an emerging technology like alkaline exchange membrane (AEM) electrolyzers. Low temperature electrolyzer technologies are first briefly introduced and the challenges thereof are presented. The non-carbon electrocatalysts are briefly overviewed, with an emphasis on the modes of action of different active phases. The main part of the review focuses on the role of carbon–metal compound active phase interfaces with an emphasis on the synergistic and additive effects. The procedures of carbon oxidative pretreatment and an overview of metal-free carbon catalysts for OER are presented. Then, the successful synthesis protocols of composite materials are presented with a discussion on the specific catalytic activity of carbon composites with metal hydroxides/oxyhydroxides/oxides, chalcogenides, nitrides and phosphides. Finally, a summary and outlook on carbon-based composites for low temperature water electrolysis are presented.

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“…OMC materials were synthesized by the hard-nanocasting route using silica SBA-15 [5,23,24]. Briefly, the silica template SBA-15 was impregnated with the carbon source, a furan resin/acetone.…”

Section: Physicochemical Characterization Of Omc Supportsmentioning

confidence: 99%

Ordered Mesoporous Carbon as a Support of Pd Catalysts for CO2 Electrochemical Reduction

2020

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Ordered mesoporous carbons (OMCs) have been used as catalyst supports of Pd nanoparticles for the electrochemical reduction of CO2 in 0.1 M KHCO3. OMC with tunable porosity and morphology were obtained by the hard-template approach using synthesized SBA-15 templates. SBA-15 materials were prepared using a mass ratio of the silica precursor (TEOS) and the surfactant (P123) of 2 or 5. After removing silica particles by a purification treatment with NaOH-ethanol or HF, different OMCs were obtained, with a developed porosity (up to 1050 m2 g−1) and ordered 2D hexagonal mesostructure (p6 mm). An increase in the TEOS/P123 ratio as well as the treatment with HF resulted in a decrease in the structural ordering of the materials. Pd nanoparticles with an average size of around 3 nm were deposited on the OMC. However, larger nanoparticles were also observed, especially for the materials obtained using a mass ratio TEOS/P123 of 5. Despite these differences, electrochemical experiments showed that CO2 was successfully reduced to other species (mainly COad) for all Pd/OMC electrocatalysts. These reduced species were adsorbed on Pd active sites, inhibiting the hydrogen evolution reaction.

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Electrochemical oxidation of ordered mesoporous carbons and the influence of graphitization

Cited by 30 publications

References 61 publications

Insights on the Electrochemical Oxidation of Ordered Mesoporous Carbons

Insights on the Electrochemical Oxidation of Ordered Mesoporous Carbons

Carbon-Based Composites as Electrocatalysts for Oxygen Evolution Reaction in Alkaline Media

Ordered Mesoporous Carbon as a Support of Pd Catalysts for CO2 Electrochemical Reduction

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