Visualization and functions of surface defects on carbon nanotubes created by catalytic etching

Xia, Wei; Yin, Xiuli; Kundu, Shankhamala; Sánchez, Miguel; Birkner, Alexander; Wöll, Christof

doi:10.1016/j.carbon.2010.09.025

Cited by 23 publications

(19 citation statements)

References 30 publications

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“…CNTs have been shown to be powerful supports for electrochemical applications. [20,[31][32][33][34] Owing to their unique structural properties, [35] they possess electronic conductivity, a high specific surface area, and tunable functional groups for a defined interaction with the precursor complex of the active component. The recent development of highly active CVD catalysts for the CNT formation process [36][37][38] has made this material cheap and abundant.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting

et al. 2012

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Incipient wetness impregnation and a novel deposition symproportionation precipitation were used for the preparation of MnOx/CNT electrocatalysts for efficient water splitting. Nanostructured manganese oxides have been dispersed on commercial carbon nanotubes as a result of both preparation methods. A strong influence of the preparation history on the electrocatalytic performance was observed. The as-prepared state of a 6.5 wt. % MnOx/CNT sample could be comprehensively characterized by comparison to an unsupported MnOx reference sample. Various characterization techniques revealed distinct differences in the oxidation state of the Mn centers in the as-prepared samples as a result of the two different preparation methods. As expected, the oxidation state is higher and near +4 for the symproportionated MnOx compared to the impregnated sample, where +2 was found. In both cases an easy adjustability of the oxidation state of Mn by post-treatment of the catalysts was observed as a function of oxygen partial pressure and temperature. Similar adjustments of the oxidation state are also expected to happen under water splitting conditions. In particular, the 5 wt. % MnO/CNT sample obtained by conventional impregnation was identified as a promising catalytic anode material for water electrolysis at neutral pH showing high activity and stability. Importantly, this catalytic material is comparable to state-of-art MnOx catalyst operating in strongly alkaline solutions and, therefore, offers advantages for hydrogen production from waste and sea water under neutral, hence, environmentally benign conditions

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Section: Introductionmentioning

confidence: 99%

Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting

et al. 2012

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“…In addition to surface functionalities, surface defects can also be used to tune the property of carbon materials for different applications [17]. For example, it was found that with the increase of defects the adsorption capacity of carbon materials can be greatly enhanced [18,19]. However, as compared to chemical functionalization, the creation of surface defects has been rarely studied experimentally.…”

Section: Introductionmentioning

confidence: 99%

Creation of surface defects on carbon nanofibers by steam treatment

Shao

Pang

Xia

et al. 2013

Journal of Energy Chemistry

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“…During synthesis, just like oxygen, fluorine and chlorine are reactive elements that can induce defects in the graphitic structure of CNTs[8]. Defective carbon structures are more reactive than their graphitic counterparts, thus, they readily accept the incorporation of heteroatoms such as nitrogen species into their structure[47]. Consequently, fluorine and chlorine in the halogenated catalysts may have enhanced nitrogen-doping levels via defects.…”

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confidence: 99%

A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

Ombaka

Ndungu

Omondi

et al. 2016

Journal of Solid State Chemistry

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Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN,-CF 3 and-Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF 3 catalyst indicates that steric factors influence the X-ray structure of 1,1′-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF 3 catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and are less thermally stable compared with those synthesised by use of the para-CN and-Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogendoping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF 3 and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and-Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF 3 catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials.

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Visualization and functions of surface defects on carbon nanotubes created by catalytic etching

Cited by 23 publications

References 30 publications

Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting

Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting

Creation of surface defects on carbon nanofibers by steam treatment

A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

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