Surface Oxidation of Carbon Nanofibres

Ros, T.G.; Dillen, A.J. van; Geus, J.W.; Koningsberger, D.C.

doi:10.1002/1521-3765(20020301)8:5<1151::aid-chem1151>3.0.co;2-#

Cited by 317 publications

(263 citation statements)

References 35 publications

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“…These include the hydrogenation of light alkenes [23][24][25][26][27], aldehydes [21,[28][29][30][31][32][33], polycyclic aromatic hydrocarbons [34], nitrobenzene [35], and cyclohexene [36]. They have also been used in alkene hydroformylation [37], vacuum residue hydroprocessing [38,39], ammonia and Fisher-Tropsch synthesis [40][41][42], cyclohexanol dehydrogenation [43], NO decomposition [44] and aniline oxidation [45,46].…”

Section: Introductionmentioning

confidence: 99%

Bio-oil upgrading in supercritical water using Ni-Co catalysts supported on carbon nanofibres

Remón

Arauzo

García

et al. 2016

Fuel Processing Technology

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This work addresses the preparation, characterisation and screening of different Ni-Co catalysts supported on carbon nanofibres (CNFs) for use in the upgrading of bio-oil in supercritical water. The aim is to improve the physicochemical properties of bio-oil so that it can be used as a fuel. The CNFs were firstly oxidised in HNO 3 and afterwards subjected to a thermal treatment to selectively modify their surface chemistry prior to the incorporation of the metal active phase (Ni-Co). The CNFs and the supported catalysts were thoroughly characterised by several techniques, which allowed a relationship to be established between the catalyst properties and the upgrading results.The use of Ni-Co/CNFs for bio-oil upgrading in supercritical water (SCW) significantly improved the properties of the original feedstock. In addition, the thermal treatment to which the fibres were subjected exerted a significant influence on their catalyticproperties. An increase in the severity of the thermal treatment led to a substantial reduction in the oxygen content of the CNFs, mainly due to the removal of the less 2 stable oxygen surface groups, which allowed their surface polarity to decrease. This decrease resulted in less formation of solid products. However, it also reduced the H/C and increased the O/C ratios of the upgraded liquid. Therefore, a compromise between the yield and the properties of the upgraded bio-oil was achieved with a Ni-Co supported on a CNF with a moderate amount of oxygen surface groups.

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Section: Introductionmentioning

confidence: 99%

Bio-oil upgrading in supercritical water using Ni-Co catalysts supported on carbon nanofibres

Remón

Arauzo

García

et al. 2016

Fuel Processing Technology

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“…From the perspective of supporting metal-containing species on CNFs, as is the case in their application as catalyst supports, functionalization of the nanofibres is in some cases a prerequisite. Through treatment with strong oxidizing media, oxygenated groups can be introduced onto the surface of CNF [5][6][7]. The number and type of these oxygen-containing moieties is highly dependent on the method of preparation.…”

Section: Introductionmentioning

confidence: 99%

Combined XPS and TPD study of oxygen-functionalized carbon nanofibers grown on sintered metal fibers

Rosenthal

Ruta

Schlögl

et al. 2010

Carbon

195

126

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A B S T R A C TA composite material consisting of carbon nanofibers (CNFs) grown on sintered metal fiber filters was modified by H 2 O 2 or plasma-generated O 3 . Coupling temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) techniques in the same UHV apparatus allowed the direct correlation of the nature of the created O-functional groups and their evolution as CO and CO 2 upon heating. The two oxidative treatments yielded different distributions of O-containing groups. The relative contribution of oxidized carbon was very low in the C1s region, hence the functional groups were more robustly analyzed through the O1s region. The comparison of the released oxygen by integration of the TPD CO, CO 2 and H 2 O spectra with the intensity loss of the XPS O1s spectra showed good agreement. In order to fit the data adequately, the set of O1s spectra was deconvoluted in at least four peaks for the differently activated samples. Finally, it was shown that functional groups formed by H 2 O 2 -treatment (mostly non-phenolic OH groups) are more thermally stable than those formed by O 3 -treatment. The latter treatment increases the concentration of carboxylic functionalities, which decompose at temperatures < 800 K;O 3 -activated CNFs should therefore show a more pronounced acidic behavior.

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“…Hydrogenation experiments and the singlestage synthesis of MIBK were performed in a semi-batch slurry reactor operating at a constant pressure of 1.2 bar H 2 at 313 K [25,35]. The set-up consisted of a thermostated stirred doublewalled glass reactor, equipped with baffles and a gas-tight mechanical stirrer.…”

Section: Catalytic Testsmentioning

confidence: 80%

“…To an aqueous solution (70 ml) containing 0. 35 To activate HT as [32,33] it was heated in a nitrogen flow to 723 K (10 K min À1 ) for 8 h and allowed to cool down to room temperature (HT heat ). HT heat was rehydrated by suspending it in decarbonated water under N 2 atmosphere for 1 h. Next, the sample was filtered under N 2 atmosphere and dried in N 2 flow at 293 K. The sample is further denoted as HT re .…”

Section: Preparation Of the Hydrotalcite Materialsmentioning

confidence: 99%

“…The difference in TOF was found to be as large as 30 times that for the MO hydrogenation and 11 times that for the cyclohexene hydrogenation. Such large differences have not been reported earlier for hydrogenation of cyclohexene using Rh and Pd catalysts [35,53]. Jackson et al [53] studied the hydrogenation of cyclohexene over Pd/alumina, Pd/carbon, Pd/silica and Pd/ zirconia catalysts and found relatively small variations in the TOF, that is, differences only up to a factor of 2.…”

Section: Hydrogenation Of Mo and Cyclohexenementioning

confidence: 99%

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A hydrotalcite-based catalyst system for the single-stage liquid-phase synthesis of MIBK

Winter

Wolters

Dillen

et al. 2006

Applied Catalysis A: General

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A comparative study was performed between Pd supported on activated hydrotalcites bi-functional catalysts and physical mixtures of activated hydrotalcites with Pd supported on carbon nanofibers for the single-stage liquid-phase synthesis of methyl isobutyl ketone from acetone and H 2 . Since it was found earlier that the dehydration reaction of diacetone alcohol over activated hydrotalcites is the rate-determining step in this process, Mg-Al hydrotalcites were investigated in the condensation of acetone to diacetone alcohol and its dehydration to mesityl oxide to enhance the activity. A correlation between the number of active base sites, as determined by volumetric CO 2 adsorption measurements at low pressures, and the activity in the dehydration reaction could be derived. A dependency on the Pd-loading (0-1 wt%) of Pd supported on activated hydrotalcites catalysts was found in the single-stage synthesis of methyl isobutyl ketone, whereas no such an effect was found when using physical mixtures of activated hydrotalcites with Pd on carbon nanofibers. Results from TEM, CO 2 chemisorption and N 2 physisorption as well as catalytic experiments in the hydrogenation of mesityl oxide and of cyclohexene indicate that this dependency is largely accounted for by entrapment of Pd particles in the agglomerates of the irregular stacks of hydrotalcite platelets, making these sites inaccessible for the reactants. #

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Surface Oxidation of Carbon Nanofibres

Cited by 317 publications

References 35 publications

Bio-oil upgrading in supercritical water using Ni-Co catalysts supported on carbon nanofibres

Bio-oil upgrading in supercritical water using Ni-Co catalysts supported on carbon nanofibres

Combined XPS and TPD study of oxygen-functionalized carbon nanofibers grown on sintered metal fibers

A hydrotalcite-based catalyst system for the single-stage liquid-phase synthesis of MIBK

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