Characterization of the surface chemistry of carbon materials by potentiometric titrations and temperature-programmed desorption

Gorgulho, Honória F.; Mesquita, João Paulo de; Gonçalves, F.; Pereira, M.F.R.; Figueiredo, José L.

doi:10.1016/j.carbon.2008.06.045

Cited by 168 publications

(87 citation statements)

References 32 publications

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“…Two functional groups on the surface in the carboxylate region (pK 2.0-5.0) [20] with pK a = 3.40 ± 0.05 (number of sites = 900 ± 30 mmol/g) and pK a = 5.5 ± 0.1 (number of sites = 240 ± 30 mmol/g) respectively, have been identified. The higher pK a value (5.5) is ascribable to the presence of lactones and carboxylic anhydride groups that tend to hydrolyze in the presence of acids and bases [21]. It is noteworthy that the number of sites attributable to carboxylic acid sites is significantly higher with respect to the value estimated by the THA method and more consistent with literature data referring to related materials such as graphite oxide [22].…”

Section: Resultssupporting

confidence: 71%

Tuning the surface morphology of self-assembled graphene-like thin films through pH variation

Alfè

Gargiulo

Capua³

2015

Applied Surface Science

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Section: Resultssupporting

confidence: 71%

Tuning the surface morphology of self-assembled graphene-like thin films through pH variation

Alfè

Gargiulo

Capua³

2015

Applied Surface Science

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“…Table 1 presents the results of proximate and ultimate analysis along with the textural characteristics of the samples. It is observed from the table that amine grafting decreases surface area and pore volume of the samples, as widely reported by others (Gorgulho et al 2008;Marcoux et al 2007;Pittman et al 1997a, b, c;Torres et al 2006). This can be interpreted in terms of pore blockage by functional groups attached on the surface.…”

Section: Co 2 Capture Measurementssupporting

confidence: 73%

Carbon Dioxide Capture with Amine-Grafted Activated Carbon

Houshmand

Daud

Lee

et al. 2011

Water Air Soil Pollut

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There are several possible methods by which amine groups can be grafted on the surface of activated carbon (AC) to improve their capacity for CO 2 adsorption. Ethylenediamine and diethylenetriamine were selected as amino compounds for anchoring on the surface of an oxidized AC. Oxidation of AC was carried out by concentrated nitric acid. For each amino compound, two "in-solvent" and "solventfree" methods with a number of grafting times were studied. Nitrogen adsorption-desorption at 77 K and proximate and ultimate analysis were used to determine physical and chemical characteristics of the samples. Temperature-programmed (TP) CO 2 adsorption test from 30°C to 120°C were performed to investigate the effect of modification on CO 2 capture. The modification clearly had a negative effect on the textural characteristics of the samples, so the samples showed a less CO 2 uptake at lower temperatures. However, the decrease of capture capacity with increasing temperature is to somewhat softer for amine-grafted samples, so that they have a capacity comparable to the parent sample or even more than that at elevated temperatures. This property may give the new adsorbents this opportunity to be used at flue gas temperature with a higher efficiency. CO 2 capture capacity per unit surface area of all the amine-modified samples, however, was significantly improved, compared to the parent sample presenting a great influence of amino groups on the CO 2 capture capacity. Moreover, the used amine compounds and grafting methods were compared in terms of adsorbent characteristics and CO 2 uptake curves. Cyclic adsorption-desorption tests showed a satisfactory regeneration for the modified samples.

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“…Scheme 1 shows the main functional groups identified on CNT surfaces after the HNO 3 treatment. [18,[27][28][29][30] Among them, phenolic, lactonic, quinonic, and carboxylic groups are usually present in large amounts, both on SWCNTs and MWCNTs.…”

Section: Introductionmentioning

confidence: 99%

“…[4,6] Many experimental studies have been devoted to the oxidation of CNT surface by nitric acid in order to 1) identify the nature of the oxygenated surface functionalities and to quantify them, 2) evaluate the physicochemical properties of the oxidized CNTs, and 3) control the kinetics of formation of oxygenated surface groups. Several techniques, often in combination, such as chemical titration, [9,17] thermal analysis/mass spectroscopy, [18,19] X-ray photoelectron spectroscopy (XPS), [20][21][22][23] FTIR spectroscopy, [21,24] and X-ray absorption near edge structure (XANES) analysis [25,26] have been used to elucidate the chemical nature of the oxygenated surface groups. Scheme 1 shows the main functional groups identified on CNT surfaces after the HNO 3 treatment.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Studies on the Carbon‐Nanotube Surface Oxidation by Nitric Acid: Interplay between Functionalization and Vacancy Enlargement

Gerber

Oubenali

Bacsa

et al. 2011

Chemistry A European J

103

102

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The nitric acid oxidation of multiwalled carbon nanotubes leading to surface carboxylic groups has been investigated both experimentally and theoretically. The experimental results show that such a reaction involves the initial rapid formation of carbonyl groups, which are then transformed into phenol or carboxylic groups. At room temperature, this reaction takes place on the most reactive carbon atoms. At higher temperatures a different mechanism would operate, as evidenced by the difference in activation energies. Experimental data can be partially related to first-principles calculations, showing a multistep functionalization mechanism. The theoretical aspects of the present article have led us to propose the most efficient pathway leading to carboxylic acid functional groups on the surface. Starting from mono-vacancies, it ends up with the synergistic formation of dangling -COOH groups and the enlargement of the vacancies.

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Characterization of the surface chemistry of carbon materials by potentiometric titrations and temperature-programmed desorption

Cited by 168 publications

References 32 publications

Tuning the surface morphology of self-assembled graphene-like thin films through pH variation

Tuning the surface morphology of self-assembled graphene-like thin films through pH variation

Carbon Dioxide Capture with Amine-Grafted Activated Carbon

Theoretical and Experimental Studies on the Carbon‐Nanotube Surface Oxidation by Nitric Acid: Interplay between Functionalization and Vacancy Enlargement

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