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Bimetallic nanoparticles (NPs) have aroused interest in various fields because of their synergetic and unique properties. Among those nanoparticles, we strategically approached and synthesized Au@Pt NPs via the sonochemical method with different molar ratios (e.g. 3:7, 5:5, and 7:3) of Au to Pt precursors. The particle structure was confirmed to be core-shell, and the size was estimated to be 60, 52, and 47 nm, respectively, for 3:7, 5:5, and 7:3 ratios of Au to Pt. The detailed structure and crystallinity of as-prepared Au@Pt NPs were further studied by scanning electron microscopy, transmission electron microscopy with element mapping, and X-ray diffraction. It should be noted that thickness of the dendritic Pt shell in the core-shell structure can be easily tuned by controlling the molar ratio of Au to Pt. To explore the possibility of this material as glucose sensor, we confirmed the detection of glucose using amperometry. Two dynamic ranges in a calibration plot were displayed at 0.5-50.0 µM and 0.05-10.0 mM, and their detection limit as glucose sensor was determined to be 319.8 (±5.4) nM.

The zeolitic imidazolate frameworks (ZIFs) ZIF-8 and ZIF-67 are well-known as belonging to the series of metal-organic frameworks. Using different types of metal ions in them, such as Zn2+ and Co2+ simultaneously, brings both advantages and disadvantages with respect to the carbonization process. For tailoring their properties, we suggest that the best approach involves control of the bimetallic ZIF-derived carbon nanoarchitecture, which is hybridized through the synergistic effects of each metal ion. In this study, the bimetallic ZIFs were designed by controlling the molar ratio of zinc (Zn2+) and cobalt (Co2+) ions, and the carbon nanoarchitecture was subsequently formed by a facile heat treatment and acid leaching. We demonstrate this approach to achieve tailored ZIF derived carbon nanoarchitectures with different pore sizes, surface areas, and degree of graphitization. These pave the way to finding the optimal carbon nanoarchitecture for specific applications such as Li-O2 air cell.

To develop powerful wind turbine generators using superconducting technology, highperformance superconducting racetrack coils are essential. Herein, we report an evaluation of a multifilamentary magnesium diboride (MgB2) conductor-based racetrack coil cooled and impregnated simultaneously by solid nitrogen (SN2). The coil was wound on a copper former with 13 mm winding width, an inner diameter of 124 mm at the curvature, and 130 mm length of the straight section. An in situ processed S-glass-insulated 36-filament MgB2 wire was wound on the former in two layers with 19.5 turns, and heat treated via the wind and react method without any epoxy resin. The coil was evaluated for critical temperature and transport critical current in the SN2 environment at different temperatures up to 31.3 K in self-field. The coil was able to carry 200 A transport current at 28.8 K in self-field. During coil charging and operation, SN2 effectively acted as an impregnation material. The test results demonstrate the viability to use MgB2 racetrack coil potentially with SN2 impregnation in advanced rotating machine applications.

In the present work, we report on the role of the methanol medium and ball-milling time in the substitution of carbon in carbon nanotube CNT-MgB 2 superconductors. In our samples, we find that the CNTs are intact and well dispersed. However, the liquid medium (methanol) used for dispersion of the constituent materials is also acting as a source of C for substitution. However, the substitution of C from methanol is not direct; rather, B 2 O 3 , which had been considered as just an impurity, plays a positive role in binding the methanol molecules to the surface of B. The detailed mechanism of methanol absorption and the role of B 2 O 3 and ball-milling time are presented here. In addition, we present the J C (H, T) data, which show that approximately 3% of C substitution provides the best critical current density at 20 K.