Synthesis of hydroxylated group IV metal oxides inside hollow graphitised carbon nanofibers: nano-sponges and nanoreactors for enhanced decontamination of organophosphates

Astle, Maxwell A.; Rance, Graham A.; Fay, Michael W.; Notman, Stuart; Sambrook, Mark R.; Khlobystov, Andrei N.

doi:10.1039/c8ta08100j

Cited by 17 publications

(24 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides that, due to their wide range of pharmacological action, they may be used for the creation of new drugs [205,206] and also as reagents in fine organic synthesis [207][208][209][210][211]. All this makes it relevant to consider the conformational properties of these compounds inside nanotubes, from the perspectives of nanoreactors [68][69][70][71][72][73][74][75] and drug delivery systems [15,19].…”

Section: 3-dioxane In Nanotubesmentioning

confidence: 99%

“…On the other hand, the calculated energy barrier for Cl − exchange in the S N 2 reaction within nanotubes was higher by 6.6 kcal/mol in comparison with the gas phase [69]. Later, it was shown that SWCNTs may be used as effective nanoreactors for preparative syntheses of inorganic [70] and organic [71][72][73][74][75] products with high yields; it is also possible to achieve enantiomeric excess of the products by using a racemic mixture of P and M enantiomers of (n,m) chiral nanotubes [76].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stereochemistry of Simple Molecules inside Nanotubes and Fullerenes: Unusual Behavior of Usual Systems

Кузнецов

2020

Molecules

View full text Add to dashboard Cite

Over the past three decades, carbon nanotubes and fullerenes have become remarkable objects for starting the implementation of new models and technologies in different branches of science. To a great extent, this is defined by the unique electronic and spatial properties of nanocavities due to the ramified π-electron systems. This provides an opportunity for the formation of endohedral complexes containing non-covalently bonded atoms or molecules inside fullerenes and nanotubes. The guest species are exposed to the force field of the nanocavity, which can be described as a combination of electronic and steric requirements. Its action significantly changes conformational properties of even relatively simple molecules, including ethane and its analogs, as well as compounds with C−O, C−S, B−B, B−O, B−N, N−N, Al−Al, Si−Si and Ge−Ge bonds. Besides that, the cavity of the host molecule dramatically alters the stereochemical characteristics of cyclic and heterocyclic systems, affects the energy of pyramidal nitrogen inversion in amines, changes the relative stability of cis and trans isomers and, in the case of chiral nanotubes, strongly influences the properties of R- and S-enantiomers. The present review aims at primary compilation of such unusual stereochemical effects and initial evaluation of the nature of the force field inside nanotubes and fullerenes.

show abstract

Section: 3-dioxane In Nanotubesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stereochemistry of Simple Molecules inside Nanotubes and Fullerenes: Unusual Behavior of Usual Systems

Кузнецов

2020

Molecules

View full text Add to dashboard Cite

show abstract

“…[34] Molybdenum dioxide bisacetylacetonate (MoO 2 (acac) 2 ) was thus identified as an ideal precursor and adopted for the gas-phase thermal deposition reaction. [34] Molybdenum dioxide bisacetylacetonate (MoO 2 (acac) 2 ) was thus identified as an ideal precursor and adopted for the gas-phase thermal deposition reaction.…”

Section: Synthesis and Characterization Of Molybdenum Dioxide Nanoparmentioning

confidence: 99%

Molybdenum Dioxide in Carbon Nanoreactors as a Catalytic Nanosponge for the Efficient Desulfurization of Liquid Fuels

Astle

Rance

Loughlin

et al. 2019

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

The principle of a "catalytic nanosponge" that combines the catalysis of organosulfur oxidation and sequestration of the products from reaction mixtures is demonstrated. Group VI metal oxide nanoparticles (CrO x , MoO x , WO x ) are embedded within hollow graphitized carbon nanofibers (GNFs), which act as nanoscale reaction vessels for oxidation reactions used in the decontamination of fuel. When immersed in a model liquid alkane fuel contaminated with organosulfur compounds (benzothiophene, dibenzothiophene, dimethyldibenzothiophene), it is found that MoO 2 @GNF nanoreactors, comprising 30 nm molybdenum dioxide nanoparticles grown within the channel of GNFs, show superior abilities toward oxidative desulfurization (ODS), affording over 98% sulfur removal at only 5.9 mol% catalyst loading. The role of the carbon nanoreactor in MoO 2 @GNF is to enhance the activity and stability of catalytic centers over at least 5 cycles. Surprisingly, the nanotube cavity can selectively absorb and remove the ODS products (sulfoxides and sulfones) from several model fuel systems. This effect is related to an adsorptive desulfurization (ADS) mechanism, which in combination with ODS within the same material, yields a "catalytic nanosponge" MoO 2 @GNF. This innovative ODS and ADS synergistic functionality negates the need for a solvent extraction step in fuel desulfurization and produces ultralow sulfur fuel.

show abstract

“…In this study, we utilised graphitised carbon nanofibres (GNF) that have many of the attractive properties of carbon nanotubes, but with the added benefits of (i) large internal diameters (typically larger than 60 nm) enabling the efficient mass transport of reactants and products to and from the internal cavity and (ii) corrugated internal surfaces resulting in the effective stabilisation of nanoparticles, as demonstrated in our previous studies (Figure 1). [33][34][35][36] Herein, successfully prepared ceria nanoparticles within GNF (CeO2@GNF) were analysed by a variety of structural and chemical characterisation techniques, and applied in the preparative-scale reaction of cyclohexene oxidation, revealing key features of nanoscale confinement in carbon nanoreactors important for sustainable organic synthesis. The internal diameters are much larger than the dimensions of simple molecular species (typically by more than an order of magnitude) and the termini are always open, thus facilitating highly efficient transport of molecules through the internal volume.…”

Section: Introductionmentioning

confidence: 99%

Cerium Oxide Nanoparticles Inside Carbon Nanoreactors for Selective Allylic Oxidation of Cyclohexene

et al. 2020

Self Cite

View full text Add to dashboard Cite

The confinement of cerium oxide nanoparticles within hollow carbon nanostructures has been achieved and harnessed to control the oxidation of cyclohexene. Graphitised carbon nanofibres (GNF) have been used as the nanoscale tubular host and filled by sublimation of the Ce(tmhd)4 complex (where tmhd = tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)) into the internal cavity, followed by a subsequent thermal decomposition to yield the hybrid nanostructure CeO2@GNF, where nanoparticles are preferentially immobilised at the internal graphitic step-edges of the GNF.Control over the size of the CeO2 nanoparticles has been demonstrated within the range c.a. 4 to 9 nm by varying the mass ratio of the Ce(tmhd)4 precursor to GNF during the synthesis. CeO2@GNF were effective in promoting the allylic oxidation of cyclohexene, in high yield, with timedependent control of product selectivity, at a comparatively low loading of CeO2 of 0.13 mol%.Unlike many of the reports to date where ceria catalyses such organic transformations, we found the encapsulated CeO2 to play the key role of radical initiator due to the presence of Ce 3+ included in the structure, with the nanotube acting as both a host, preserving the high performance of the CeO2 nanoparticles, anchored at the GNF step-edges, over multiple uses, and an electron reservoir, maintaining the balance of Ce 3+ and Ce 4+ centers. Spatial confinement effects ensure excellent stability and recyclability of CeO2@GNF nanoreactors.

show abstract

Synthesis of hydroxylated group IV metal oxides inside hollow graphitised carbon nanofibers: nano-sponges and nanoreactors for enhanced decontamination of organophosphates

Abstract: The enhanced catalytic properties of hydroxylated group IV metal oxide nanostructures confined within hollow graphitised carbon nanofibers has been demonstrated.

Cited by 17 publications

References 45 publications

Stereochemistry of Simple Molecules inside Nanotubes and Fullerenes: Unusual Behavior of Usual Systems

Stereochemistry of Simple Molecules inside Nanotubes and Fullerenes: Unusual Behavior of Usual Systems

Molybdenum Dioxide in Carbon Nanoreactors as a Catalytic Nanosponge for the Efficient Desulfurization of Liquid Fuels

Cerium Oxide Nanoparticles Inside Carbon Nanoreactors for Selective Allylic Oxidation of Cyclohexene

Contact Info

Product

Resources

About