Growth of nitrogen-doped filamentous and spherical carbon over unsupported and Y zeolite supported nickel and cobalt catalysts

Nieto-Márquez, Antonio; Lazo, José C.; Romero, Amaya; Valverde, J.L.

doi:10.1016/j.cej.2008.07.046

Cited by 13 publications

(9 citation statements)

References 46 publications

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“…In a later work, the growth of structured carbon from the decomposition of acetonitrile over Ni and Co catalysts was examined. 49 When increasing reaction temperature, the carbon obtained, present initially as smooth filaments, increased the lattice segmentation to finally stand as CNS at 1150 C. This observation was further investigated in the absence of catalyst, demonstrating that at such temperature, the spheres were produced via a thermal rather than a catalytic route. The above research suggests that the growth of CNS is highly temperature demanding, and while the catalyst may play some role in assisting carbon growth and determining some lattice structure, further growth may proceed by a pyrolytic mechanism.…”

Section: Jos E Luis Valverdementioning

confidence: 88%

Carbon nanospheres: synthesis, physicochemical properties and applications

et al. 2011

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The discovery of carbon nanostructures, essentially carbon nanotubes (CNT) and carbon nanofibres (CNF) has led to a big effort devoted to their synthesis, characterization, surface modification and use. Indeed, these structures have encountered application in a wide range of technological fields, such as adsorption, catalysis, hydrogen storage or electronics. Apart from the filamentous arrange of graphene sheets conducting to CNT or CNF, carbon can bond in other different ways to create structures with dissimilar properties. The pairing of pentagonal and heptagonal carbon rings can result in the formation of carbon nanospheres (CNS). This novel nanostructure has only now started to attract significant research activity. In its spherical arrangement, the graphite sheets are not closed shells but rather waving flakes that follow the curvature of the sphere, creating many open edges at the surface. Contrary to the chemically inert C 60 , the unclosed graphitic flakes provide reactive ''dangling bonds'' that are proposed to enhance surface reactions, establishing CNS as good candidates for catalytic and adsorption applications. Despite the embryonic stage of the field and the existing data being too scattered, this work is aimed to provide a comprehensive review of the existing literature related to CNS, exploring the different preparation routes employed, the critical characterization results as well as the applications studied so far.

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Section: Jos E Luis Valverdementioning

confidence: 88%

Carbon nanospheres: synthesis, physicochemical properties and applications

et al. 2011

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“…Most methods produce CNTs with by-products such as amorphous carbon that necessitate additional purification steps (Nieto-Márquez et al 2008;Matlhoko et al 2009). The disadvantages of the arc discharge and laser ablation processes are (1) these processes are not very well controlled, nor are they continuous; (2) the removal of impurities with simple, cheap purification methods is difficult;…”

Section: Synthesis Of N-cntsmentioning

confidence: 99%

“…They can be applied as field emission electron sources, for flat panel displays, lamps and gas discharge tubes providing surge protection and as X-ray and microwave generators (Fan et al 2006). Nieto-Márquez et al (2008) revealed that CNTs possess fascinating physical and chemical properties with electronic behaviour varying from metallic to semiconducting depending on their structural composition, chirality and diameter. It is still a challenge to precisely control these parameters in the growth process of the CNTs and hence it is also not easy to control the properties or the reactivity of the CNT outer wall (Tao et al 2007).…”

Section: Cntsmentioning

confidence: 99%

Nitrogen-doped carbon nanotubes as a metal catalyst support

et al. 2011

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The science and technology of catalysis is of fundamental importance to a national economy. Today about 90% of all technical chemicals are manufactured by the use of catalysts. Nanoparticles of noble metals are extremely important materials in the catalysis industry due to cost issues and properties that are not found in their bulk state. An efficient way to produce and stabilise noble metal nanoparticles is by dispersion on a suitable support. Carbon-based supports, such as carbon nanotubes, carbon spheres, carbon fibres, etc., have been found to be good supports for metal nanoparticles. However, to be used effectively, the carbon surface must be modified either by functionalisation or doping. This review discusses the synthesis and the possible applications of nitrogen-doped carbon nanotubes as supports for metal nanoparticles in heterogeneous catalysis.

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“…It is difficult to obtain pure cobalt and nickel compounds because their similar physicochemical properties. With the ever-increasing need of cobalt and nickel in alloy, battery and catalyst [1][2][3], much effort has been devoted for developing their separation technology, such as liquid membrane [4], microemulsion extraction [5], hollow fiber membrane [6], electrodialysis [7] and reversed micelle [8]. It worth well noted that cobalt and nickel are hazardous metals, lots of industrial activities concerning the contaminants pose a threat to ecosystems [9].…”

Section: Introductionmentioning

confidence: 99%