Effect of electrochemical treatments on the surface chemistry of activated carbon

Berenguer, R.; Marco-Lozar, J.P.; Quijada, C.; Cazorla‐Amorós, Diego; Morallón, Emilia

doi:10.1016/j.carbon.2008.12.022

Cited by 112 publications

(76 citation statements)

References 31 publications

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“…After the electro-oxidation of P-groups, and in accordance with the experimental results previously shown, and although some carbon active sites could be directly electroxidized [49,50], we propose that during the electro-oxidation treatments, most of the oxidation proceeds through the initial and freshly-generated oxidized phosphorus species that transfer the gained oxygen to neighboring carbon atoms, acting as mediators of carbon electroxidation. In particular, among different phosphorus species, it is suggested that the mediated reaction may require of -C-O-P-connections, like in the case of mix -C-O-P-C-or -C-O-P-species.…”

Section: Accepted Manuscriptsupporting

confidence: 63%

“…A possible reaction pathway for the initial transformations that take place in P groups is represented in the Figure 6. This electrochemical oxidation (oxygen uptake) may involve the nucleophilic attack of surface atoms by hydroxyl radicals, electrochemically generated from water at high potentials on the electrode surface [49,50], which must be favored on the positively polarized graphenic layers under the electroxidation conditions.…”

Section: Mechanistic Aspectsmentioning

confidence: 99%

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Enhanced electro-oxidation resistance of carbon electrodes induced by phosphorus surface groups

Berenguer

Ruiz-Rosas

Gallardo

et al. 2015

Carbon

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ABSTRACT:The electro-oxidation of carbon materials enormously degrades their performance and limits their wider utilization in multiple electrochemical applications.In this work, the positive influence of phosphorus functionalities on the overall electrochemical stability of carbon materials has been demonstrated under different conditions. We show that the extent and selectivity of electroxidation in P-containing carbons are completely different to those observed in conventional carbons without P.The electro-oxidation of P-containing carbons involves the active participation of phosphorus surface groups, which are gradually transformed at high potentials from less-to more-oxidized species to slow down the introduction of oxygen groups on the carbon surface (oxidation) and the subsequent generation of (C*OOH)-like unstable promoters of electro-gasification. The highest-oxidized P groups (-C-O-P-like species) seem to distribute the gained oxygen to neighboring carbon sites, which finally suffer oxidation and/or gasification. So it is thought that P-groups could act as mediators of carbon oxidation although including various steps and intermediates compared to electroxidation in P-free materials.

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Section: Accepted Manuscriptsupporting

confidence: 63%

Section: Mechanistic Aspectsmentioning

confidence: 99%

Enhanced electro-oxidation resistance of carbon electrodes induced by phosphorus surface groups

Berenguer

Ruiz-Rosas

Gallardo

et al. 2015

Carbon

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“…54 We can therefore say that ZTC is easily electrochemically oxidized at an extremely low potential, compared with ordinary carbon materials. This unusual feature of ZTC could be ascribed to its unique buckybowl-like framework (Figures 1c and 1d), i.e., an extremely narrow and curved nanosized graphene.…”

Section: Resultsmentioning

confidence: 99%

Large Pseudocapacitance in Quinone-Functionalized Zeolite-Templated Carbon

Itoi

Nishihara²,

Ishii³

et al. 2013

Bulletin of the Chemical Society of Japan

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Zeolite-templated carbon (ZTC), which can be obtained as a negative replica of a zeolite, consists of buckybowllike nanographenes assembled into a three-dimensional regular network. ZTC is characterized not only by this unique framework structure but also by a very large number of carbon edge sites. In this paper, we report that the edge sites of ZTC are easily functionalized by a large amount of quinone groups through electrochemical oxidation unlike general carbonaceous materials, and the quinone-functionalized ZTC shows a high electrochemical capacitance (ca. 300 500 F g ¹1 ) in an aqueous electrolyte solution (1 M H 2 SO 4 ) as a result of the large pseudocapacitance derived from a quinone/hydroquinone redox couple. Moreover, ZTC keeps its high capacitance even after thousands of charge discharge cycles.Fullerenes, 1 single-walled carbon nanotubes (SWCNTs), 2,3 and graphenes 4,5 are nanocarbon materials with 0D, 1D, and 2D topologies, respectively. Though fullerenes form poorly conductive van der Waals crystals, SWCNTs 6,7 and graphenes 811 are electrically conductive, and are promising as electrode materials for electrochemical capacitors. 12 Their building unit, a graphene sheet, has a large theoretical surface area (2630 m 2 g ¹1 ), and therefore potentially has a large capacitance. However, the actual BrunauerEmmettTeller (BET) surface areas of SWCNTs 13 and graphenes 8 are at most 1250 and 705 m 2 g ¹1 , respectively, because of the aggregation/stacking of the graphene sheets as a result of strong van der Waals interactions. To expose the entire surface, a graphene sheet has to be formed into a self-standing 3D network, like carbon schwarzite 14,15 or pillared graphene, 16 both of which are imaginary materials and have only been proposed theoretically. Thus far our group has demonstrated that it is possible to synthesize a graphene-based architecture with a 3D topology inside the confined-nanospace network of a zeolite crystal, as shown in Figures 1a1c. 1720The zeolite-templated carbon (ZTC) thus obtained consists of a buckybowl-like nanographene assembled into a 3D regular network (Figures 1c and 1d). Both sides of the buckybowllike unit are fully exposed, and, in addition, the narrow nanographene-based framework has a significant number of edge sites. 18 Consequently, ZTC has a very large geometric (theoretical) surface area of 3432 m 2 g ¹1 , and such a large surface area has indeed been observed experimentally.18 ZTC possesses unique spin/magnetic properties 21 and is predicted to have a unique band structure. 22 Moreover, it has a high hydrogen-storage capacity 23,24 and superior performance as an electrode for electrochemical capacitors.2527 Modifications of ZTC with electrochemically active species are expected to further enhance its performance. Graphene-based materials are generally modified by doping of graphene with other functional components such as metal nanoparticles, 2830 metal oxides/ hydroxides, 3134 and conductive polymers. 35 Another modification method is to functionalize graphenes...

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“…The fact that the electrosorptive removal rate depends on applied potential shows that the overall electrosorption process is not controlled by the diffusion of BA species from bulk solution onto ACE surface [7] as observed in batch mode electrosorption of basic dyes [6]. On the other hand, it is reported that positive polarization above ~1.3 V causes oxidation of activated carbons [14,15] thus decrease the conductivity and specific surface area of electrodes. Although a relatively slight enhancement was observed by applying 2.0 V compared to the 1.5 V applied potential, 1.5 V was chosen as an optimum polarization potential for other experiments in order to avoid the further oxidation of ACEs.…”

Section: Potential Dependence Of Electrosorptionmentioning

confidence: 99%

Electrosoption of Aromatic Organic Acids From Aqueous Solutions Onto Granular Activated Carbon Electrodes for Water Purification

Bayram¹

2016

HJBC

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Ö Z E T S u arıtma sistemleri, artan insan nüfusu ve çevre kirliliği sonucunda oldukça önemli hale gelmiştir. Bu çalışmada, benzoik asit (BA) ve nikotinik asitin (NA) sulu çözeltilerinden, aktiflenmiş karbon elektrotlar (ACEs) üzerine elektrosorpsiyon yolu ile uzaklaştırılmaları incelenmiştir. ACEs, endüstriyel olarak elde edilebilen granüllü aktiflenmiş karbon ve polietilen bağlayıcı kullanılarak üretilmiştir. Elektrosorpsiyon sırasında organik moleküllerin derişimlerinde oluşan değişimler, online UV-Vis spektrofotometrik sistem kullanılarak takip edilmiştir. BA nın elektrosorsiyonu üzerine uygulanan potansiyel ve çözelti akış hızı gibi sistem parametrelerinin etkileri incelenmiştir. Optimum proses parametrelerinin, çözelti akış hızı için 60 mL.dk -1 ve ACEs polarizasyonu için 1.5 V olduğu bulunmuştur. BA ve NA içeren ikili karışımların elektrosorpsiyon davranışları da incelenmiştir. BA ve NA nın aktiflenmiş karbon elektrotlar kullanılarak sulu çözeltilerinden elektrosorpsiyon ile etkili bir şekilde uzaklaştırılabileceği sonucuna varılmıştır. Anahtar KelimelerAktiflenmiş karbon elektrot, elektrosorpsiyon, aromatik organik asitler, su arıtma. A B S T R A C TW aste water treatment systems have great importance as a result of the increasing population and environmental pollution. In this study, electrosorptive removal of benzoic acid (BA) and nicotinic acid (NA) from aqueous solutions onto activated carbon electrodes (ACEs) were studied. ACEs were fabricated from the industrially available granular activated carbon and polyethylene as binder. During the electrosorption process, the change in concentration of organic molecules was followed by using an online UV-Vis spectrophotometric system. Effects of operational parameters such as applied potential and volumetric flow rate on electrosorption of BA were examined. Optimum parameters for the process were found to be 60 mL.min -1 for volumetric flow rate and 1.5 V for polarization of ACEs. Electrosorption of binary mixtures of BA and NA was also studied. it can be concluded that BA and NA can be effectively removed by electrosorption from aqueous solutions using activated carbon electrodes.

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Effect of electrochemical treatments on the surface chemistry of activated carbon

Cited by 112 publications

References 31 publications

Enhanced electro-oxidation resistance of carbon electrodes induced by phosphorus surface groups

Enhanced electro-oxidation resistance of carbon electrodes induced by phosphorus surface groups

Large Pseudocapacitance in Quinone-Functionalized Zeolite-Templated Carbon

Electrosoption of Aromatic Organic Acids From Aqueous Solutions Onto Granular Activated Carbon Electrodes for Water Purification

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