FePt nanoparticles (NPs)/reduced graphene oxide (rG-O) composites have been synthesized using a one-pot strategy without surfactants. Monodisperse FePt NPs were homogenously loaded onto rG-O sheets. By controlling the...
FePt nanoparticles (NPs)/reduced graphene oxide (rG-O) composites have been synthesized using a one-pot strategy without surfactants. Monodisperse FePt NPs were homogenously loaded onto rG-O sheets. By controlling the concentration of dispersed graphene oxide (GO), uniform FePt flower-like nanoclusters can be obtained. FePt/rG-O composites exhibited exceptionally high electrocatalytic performance in the activity and durability for the oxygen reduction reaction (ORR), much superior to that of the commercial Pt/C (60%). The straightforward synthesis of FePt/rG-O composites provides a low-cost and high performance catalyst for the ORR, which is also a promising strategy for the synthesis of various Pt-based bimetallic alloy/rG-O composites for potential uses in catalysis and energy fields.
A new modulated structure consisting of periodic （1120） stacking faults （SFs） in the α-Fe2O3 nanowires （NWs） formed by the thermal oxidation of Fe foils is reported, using a combination of high-resolution trans...
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A new modulated structure consisting of periodic （1120） stacking faults （SFs） in the α-Fe2O3 nanowires （NWs） formed by the thermal oxidation of Fe foils is reported, using a combination of high-resolution transmission electron microscopy （HRTEM） observations and HRTEM image simulations. The periodicity of the modulated structure is 1.53 nm, which is ten times （3500） interplanar spacing and can be described by a shift of every ten （3500） planes with 1/2 the interplanar spacing of the （1120） plane. An atomic model for the Fe203 structure is proposed to simulate the modulated structure. HRTEM simulation results confirm that the modulated structure in α-Fe2O3 NWs is caused by SFs.
BiI3 is a wide band-gap compound semiconductor with a high effective atomic number that is anticipated to exhibit higher detection efficiency than other compound semiconductors such as HgI2, PbI2, and CdZnTe. This mak...
BiI3 is a wide band-gap compound semiconductor with a high effective atomic number that is anticipated to exhibit higher detection efficiency than other compound semiconductors such as HgI2, PbI2, and CdZnTe. This makes BiI3 of particular interest for moderate and high energy gamma-ray detection applications. However, the low resistivity of BiI3 results in high leakage currents and degrades the electrical properties and detecting performance of the detectors. Here we show that the main reason for the low resistivity in BiI3 is due to the high volatility of iodine and the high concentration of intrinsic Schottky defects. Furthermore, we will discuss novel defect engineering strategies that successfully mitigate the obstacles associated with iodine vacancies in the material. Density functional theory (DFT) calculations, as well as experimentally measured electrical properties, and radiation response will be presented for undoped and Sb-doped BiI3 (SBI) single crystals grown via the vertical Bridgman growth technique. Most importantly, we will demonstrate the first ever recorded gamma-ray spectrum using BiI3-based detectors.
We perform extensive coarse-grained (CG) Langevin dynamics simulations of intrinsically disordered proteins (IDPs), which possess fluctuating conformational statistics between that for excluded volume random walks and...
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We perform extensive coarse-grained (CG) Langevin dynamics simulations of intrinsically disordered proteins (IDPs), which possess fluctuating conformational statistics between that for excluded volume random walks and collapsed globules. Our CG model includes repulsive steric, attractive hydrophobic, and electrostatic interactions between residues and is calibrated to a large collection of single-molecule fluorescence resonance energy transfer data on the interresidue separations for 36 pairs of residues in five IDPs: α−, β−, and γ-synuclein, the microtubule-associated protein τ, and prothymosin α. We find that our CG model is able to recapitulate the average interresidue separations regardless of the choice of the hydrophobicity scale, which shows that our calibrated model can robustly capture the conformational dynamics of IDPs. We then employ our model to study the scaling of the radius of gyration with chemical distance in 11 known IDPs. We identify a strong correlation between the distance to the dividing line between folded proteins and IDPs in the mean charge and hydrophobicity space and the scaling exponent of the radius of gyration with chemical distance along the protein.
Transport measurements on thin films of NdNiO3 reveal a crossover to a regime of pronounced nonlinear conduction below the well-known metal-insulator transition temperature. The evolution of the transport properties a...
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Transport measurements on thin films of NdNiO3 reveal a crossover to a regime of pronounced nonlinear conduction below the well-known metal-insulator transition temperature. The evolution of the transport properties at temperatures well below this transition appears consistent with a gradual formation of a gap in the holelike Fermi surface of this strongly correlated system. As T is decreased below the nominal transition temperature, transport becomes increasingly non-Ohmic, with a model of Landau-Zener breakdown becoming most suited for describing I(V) characteristics as the temperature approaches 2 K.
The Cu(I)-catalyzed azide-alkyne cycloaddition(Cu AAC)of terminal alkyne and organic azide independently reported by Sharpless’and Meldal’s groups in 2002 has found wide applications in the areas o
The Cu(I)-catalyzed azide-alkyne cycloaddition(Cu AAC)of terminal alkyne and organic azide independently reported by Sharpless’and Meldal’s groups in 2002 has found wide applications in the areas o
The formation of novel and complex structures with specific morphologies from nanocrystals via a direct assembly of atoms or ions remains challenging. In recent years, researchers have focused their attention on nanoc...
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The formation of novel and complex structures with specific morphologies from nanocrystals via a direct assembly of atoms or ions remains challenging. In recent years, researchers have focused their attention on nanocrystals of noble metals and their controlled synthesis, characterization, and potential applications. Although the synthesis of various noble metal nanocrystals with different morphologies has been reported, most studies are limited to low-index facet-terminated nanocrystals. High-index facets, denoted by a set of Miller indices {hkl} with at least one index greater than unity, possess a high density of low-coordinated atoms, steps, edges, and kinks within these structures and serve as more active catalytic sites. With the potential for enhanced catalytic performance, researchers have used the insights from shape-controlled nanocrystal synthesis to construct noble metal nanocrystals bounded with high-index facets. Since the report of Pt tetrahexahedral nanocrystals, researchers have achieved significant progress and have prepared nanocrystals with various high-index facets. Because of the general order of surface energy for noble metals, high-index facets typically vanish faster in a crystal growth stage and are difficult to preserve on the surface of the final nanocrystals. Therefore researchers have had limited opportunities to examine high-indexed noble metal nanocrystals with a controlled morphology and investigate their resultant behaviors in depth.
In this Account, we thoroughly discuss the basic concepts and state-of-the-art morphology control of some noble metal nanocrystals enclosed with high-index facets. We briefly introduce high-index facets from both crystallographic and geometrical points of view, both of which serve as methods to classify these high-index facets. Then, we summarize various typical noble metal nanocrystals terminated by different types of high-index facets, including {hk0} (h > k > 0), {hhl} (h > l > 0), {hkk} (h > k > 0)
The study on alkyne hydrothiolations for the construction of small molecules was reported half a century ago.1 While,this reaction was almost forgotten until Bowman and co-workers developed highly
The study on alkyne hydrothiolations for the construction of small molecules was reported half a century ago.1 While,this reaction was almost forgotten until Bowman and co-workers developed highly
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