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.

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.

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

We report the structures of six new divalent transition metal hexathiocyanatobismuthate Prussian Blue analogues frameworks, which contain complex ordered defect structures.

Magnetic contrast agents are widely used in magnetic resonance imaging in order to significantly change the signals from the regions of interest in comparison with the surrounding tissue. Despite a high variety of single-mode T1 or T2 contrast agents, there is a need for dual-mode contrast from the one agent. Here, we report on the synthesis of magnetic submicron carriers, containing Fe3O4 nanoparticles in their structure. We show the ability to control magnetic resonance contrast by changing not only the number of magnetite nanoparticles in one carrier or the concentration of magnetite in the suspension but also the structure of the core–shell itself. The obtained data open up the prospects for dual-mode T1/T2 magnetic contrast formation, as well as provides the basis for future investigations in this direction.