The effects of hydrogen on thermal desorption of oxygen surface complexes

Calo, J.M.; Cazorla‐Amorós, Diego; Linares‐Solano, A.; Román-Martı́nez, M.C.; Lecea, C. Salinas-Martı́nez de

doi:10.1016/s0008-6223(96)00173-x

Cited by 87 publications

(67 citation statements)

References 10 publications

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“…288 carboxylic anhydrides (at about 500°C) [24,[37][38][39][40] and 289 phenol, carbonyl, quinone and ether groups (at higher tem-290 peratures) [24,[37][38][39][40]. In the CO 2 spectra, three peaks 291 appear.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

Chemical and electrochemical characterization of porous carbon materials

Bleda-Martı́nez

Lozano‐Castelló

Morallón

et al. 2006

Carbon

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10 Abstract 11Chemical and electrochemical techniques have been used in order to asses surface functionalities of porous carbon materials. An 12 anthracite has been chemically activated using both KOH and NaOH as activating agents. As a result, activated carbons with high 13 micropore volume (higher than 1 cm 3 /g) have been obtained. These samples were oxidized with HNO 3 and thermally treated in N 2 flow 14 at different temperatures in order to obtain porous carbon materials with different amounts of surface oxygen complexes. Thermal treat-15 ment in H 2 was also carried out. The sample treated with H 2 was subsequently treated in air flow at 450°C. Thus, materials with very 16 similar porous texture and widely different surface chemistry have been compared. The surface chemistry of the resulting materials was 17 systematically characterized by TPD experiments and XPS measurements. Galvanostatic and voltammetric techniques were used to dee-18 pen into the characterization of the surface oxygen complexes. The combination of both, chemical and electrochemical methods provide 19 unique information, regarding the key role of surface chemistry in improving carbon wettability in aqueous solution and the redox pro-20 cesses undergone by the surface oxygen groups. Both contributions are of relevance to understand the use of porous carbons as electro-21 chemical capacitors. 22

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Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

Chemical and electrochemical characterization of porous carbon materials

Bleda-Martı́nez

Lozano‐Castelló

Morallón

et al. 2006

Carbon

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235

159

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“…Thermal treatment of activated carbons causes the decomposition of surface oxygen groups, but the nascent free sites have high reactivity, and in contact with air, they will generate fresh surface oxygen groups. When hydrogen is feed during the thermal treatment, it is able to catalyze the removal of certain oxygen groups and to react with nascent free sites, deactivating them and explaining the high efficiency of this treatment for removal of surface groups (Calo et al, 1997). Regarding ACM sample, it shows a decrease in CO-evolving groups in comparison to Ank4.…”

Section: Principles For the Asymmetric Designmentioning

confidence: 99%

“…Ank4 was previously purified using aqueous solutions (10 wt.%) of HCl, HNO 3 , HF, at room temperature for 48 h. After acid treatments, Ank4 was washed with deionized water up to the final pH of the washing water and dried at 120°C overnight. Then, Ank4 was treated in U-shaped quartz reactor under a hydrogen/helium flow of 30 mL min −1 at 850°C for 3 h (named Ank_H 2 ) (Calo et al, 1997;Vilella et al, 2005).…”

Section: Activated Carbon Samplesmentioning

confidence: 99%

Design of Activated Carbon/Activated Carbon Asymmetric Capacitors

et al. 2016

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Supercapacitors are energy storage devices that offer a high power density and a low energy density in comparison with batteries. Their limited energy density can be overcome by using asymmetric configuration in mass electrodes, where each electrode works within their maximum available potential window, rendering the maximum voltage output of the system. Such asymmetric capacitors are optimized using the capacitance and the potential stability limits of the electrodes, with the reliability of the design largely depending on the accuracy and the approach taken for the electrochemical characterization. Therefore, the performance could be lower than expected and even the system could break down, if a well thought out procedure is not followed.In this work, a procedure for the development of asymmetric supercapacitors based on activated carbons is detailed. Three activated carbon materials with different textural properties and surface chemistry have been systematically characterized in neutral aqueous electrolyte. The asymmetric configuration of the masses of both electrodes in the supercapacitor has allowed to cover a higher potential window, resulting in an increase of the energy density of the three devices studied when compared with the symmetric systems, and an improved cycle life.

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“…The -C 2 O 3 surface complexes may be similar to the carboxylic anhydride complexes that have been identified as major intermediate species in the air/oxygen gasification of carbons and chars: 46,47,48 The carbonate anions in the recirculating slurry may serve as a "catalyst" to "activate" carbon particle surfaces by performing the first oxidation step to form the requisite -C(O) surface complexes. If the polarization is insufficient at the point of oxidation in the bulk melt phase to release the two electrons, the surface oxygen complex may remain charged, or the charge may be delocalized over the carbon particle.…”

Section: Design Overviewmentioning

confidence: 99%

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

Calo¹

2004

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The effects of hydrogen on thermal desorption of oxygen surface complexes

Cited by 87 publications

References 10 publications

Chemical and electrochemical characterization of porous carbon materials

Chemical and electrochemical characterization of porous carbon materials

Design of Activated Carbon/Activated Carbon Asymmetric Capacitors

Spouted Bed Electrodes (Sbe) for Direct Utilization of Carbon in Fuel Cells

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