Influence of He and N2 plasma on in situ surface passivated Fe nanopowders by plasma arc discharge

DC transferred arc plasma method was employed for the synthesis of core (Fe)-shell (Fe oxide) nanopowders under N₂ and He atmospheres. The phase and elemental compositions were studied by x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDS) techniques. The structural and magnetic properties were investigated by high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. XRD and EDS results confirmed the presence of iron and iron oxide. From HRTEM, the average particle sizes of 32, 47 and 71 nm and 20, 26 and 37 nm were obtained against processing currents of 50, 100 and 150 A under N₂ and He atmospheres respectively. The average particle size values were found to increase with increases in processing current. Spherical and hollow hexagonal nano-structures were obtained under N₂ atmosphere whereas spherical and distorted cubes were formed under He atmosphere. The elemental mapping revealed the presence of oxygen on the surface and Fe in the core of the nanoparticles.

CuI incorporated cobalt ferrite nanoparticles as a magnetically separable catalyst for oxidative amidation reaction

A Cu-incorporated magnetic nanocatalyst has been developed for oxidative amidation of aryl aldehydes with 2-aminopyridine in the presence of TBHP.

Recent developments in the synthesis and applications of graphene-family materials functionalized with cyclodextrins

The introduction of cyclodextrin species to graphene-family materials (GFMs) constitutes an important area of research, especially in terms of the development of applied nanoscience. The chemistry of cyclodextrins is the so-called host-guest chemistry, which has impacted on many fields of research, including catalysis, electrochemistry and nanomedicine. Cyclodextrins are water-soluble and biocompatible supramolecules, and therefore they may introduce new interesting properties to GFMs and may enhance the physicochemical/biological features of native GFMs. The reported methods for the conjugation of cyclodextrins to GFMs utilize either covalent or non-covalent approaches. The recent progress in the applications of GFMs functionalized with cyclodextrins, with the respect to the chemistry and features of these conjugates, is discussed. Special consideration is also given to the recent developments in (i) nanomedicine, (ii) electrochemistry, (iii) adsorption and (iv) catalysis. Examples of these materials are discussed in this work, together with the future outlook on the impact of GFM-cyclodextrin conjugates in the development of applied nanoscience.