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.

This paper presents a simple and convenient procedure for the preparation of octyl amine capped silver nanoparticles. AgNO 3 has been reduced by octyl amine with benzene or toluene as solvent at 100°C to produce silver nanoparticles. Octyl amine plays its role both as reducing and capping agent and thus provides the advantage of avoiding the use of extra stabilizing agent. Time dependent formation mechanism of silver nanoparticle has been investigated. Thermo gravimetric analysis (TGA) shows weight change due to loss of capping agent. The reaction can easily be monitored from variation of color with time. The method is easy and reproducible. Very low concentration (1 mM) of metal ion is used. The particles synthesized were characterized by UV-Visible, FTIR, TGA, TEM and X-ray diffraction studies.

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