Activated microwave-exfoliated graphite oxide combined with an ionic liquid can be used to make enhanced capacitor.

Equilibrium concentrations of dissolved platinum species from a electrocatalyst sample in 0.5 M at 80°C were found to increase with applied potential 0.9 1.1 V vs reversible hydrogen electrode. In addition, surface area loss for short-stack proton exchange membrane fuel cells (PEMFCs) operated open-circuit voltage was shown be higher than another under load . Both findings suggest that the formation soluble (such as ) plays an important role PEMFC electrodes. As accelerated cathode (from 63...

Li[Li0.2Ni0.2Mn0.6]O2, which is a cathode material for Li-ion batteries with enhanced capacity, has been examined, the first time, combination of aberration-corrected scanning transmission electron microscopy (STEM), STEM computer simulations, and diffraction (D-STEM). These techniques, in X-ray (XRD) conventional (ED), indicate that this composed solid solution C2/m monoclinic symmetry multiple planar defects. In addition, we show XRD ED alone can give misleading information cannot resolve...

The enhancement of Pt nanoparticle anchoring strength and dispersion on carbon supports is highly desirable in polymer electrolyte membrane fuel cells (PEMFCs) as well other catalysis processes. Presented here a comprehensive study the interaction between catalyst nanoparticles terms electronic structure change its effects electrocatalytic performance supported catalysts. Graphene was chosen an ideal model support because unique 2-D allows direct investigation with metal at their interface....

Atomically resolved structures and compositions of Pt alloy nanoparticles were obtained using aberration-corrected high-angle dark field imaging, which was correlated to specific ORR activity based on a surface area. The enhanced (∼2 times relative Pt) acid-treated "Pt3Co" can be related composition variations at the atomic scale formation percolated Pt-rich Pt-poor regions within individual particles. Upon annealing, we show direct evidence sandwich-segregation structures, correspond ∼4 Pt.

Rotating disk electrode measurements of acid-treated "Pt3Co" nanoparticles showed specific oxygen reduction reaction (ORR) activity (∼0.7 mA/cmPt2 at 0.9 V vs RHE in 0.1 M HClO4 room temperature), twice that Pt nanoparticles. Upon annealing 1000 K vacuum, the ORR was increased to ∼1.4 (four times nanoparticles). High-resolution transmission electron microscopy and aberration-corrected high-angle annular dark-field scanning microscope used reveal surface atomic structure chemical composition...

We demonstrate an efficient and rapid microwave irradiated solvothermal method to prepare nanostructured lithium metal phosphates LiMPO(4) (M = Mn, Fe, Co, Ni) within a short reaction time (5-15 min) at temperatures as low 300 degrees C without requiring any post annealing elevated temperatures. The highly viscous, high-boiling tetraethyleneglycol used the solvent not only provides reducing atmosphere prevent oxidation of M(2+) M(3+) but also inhibits agglomeration nanoparticles formed....

An aberration-corrected JEOL 2200FS scanning-transmission electron microscope (STEM), equipped with a high-angle annular dark-field detector (HAADF), is used to monitor the coalescence and sintering of Pt nanoparticles an average diameter 2.8 nm. This in situ STEM capability combined analysis methodology that together allows direct measurements mass transport phenomena are important understanding how particle size influences at nanoscale. To demonstrate feasibility this methodology, surface...

In situ heating experiments were performed in a transmission electron microscope (TEM) to monitor the thermal stability of silver nanoparticles. The sublimation kinetics from isothermal on individual nanoparticles was used assess actual temperatures by considering localized beam. For isolated nanoparticles, beam under normal TEM operating conditions found increase temperature tens degrees. nominally experiments, observed generally decreased with decreasing particle size, agreement...

Nanocrystalline metals demonstrate a range of fascinating properties, including high levels mechanical strength. However, as these materials are exposed to temperatures, it is critical determine the grain size evolution, this process can drastically change properties. In work, nanocrystalline sputtered Cu thin films with 43 +/- 2 nm were produced by dc-magnetron sputtering. Specimens subsequently annealed in situ transmission electron microscope at 100, 300 and 500 degrees C. Not only was...

The synthesis and characterization of poly(phenylene methylene) (PPM) carbon composites thereof are described. materials were prepared using graphite oxide (GO), which was discovered to function in two distinct roles. First, the GO found facilitate dehydrative polymerization benzyl alcohol (BnOH) form PPM. Second, residual from catalyst, having undergone thermal deoxygenation during reaction, served as a graphene-like additive resulting composite. While pure (i.e., additive-free) PPM be...

Five membrane-electrode assemblies (MEAs) with different average sizes of platinum (Pt) nanoparticles (2.2, 3.5, 5.0, 6.7, and 11.3 nm) in the cathode were analyzed before after potential cycling (0.6 to 1.0 V, 50 mV/s) by transmission electron microscopy. Cathodes loaded 2.2 3.5 nm catalyst exhibit following changes during electrochemical cycling: (i) substantial broadening size distribution relative initial distribution, (ii) presence coalesced particles within electrode, (iii)...

The influence of synthesis temperature and time on the length (capacity) plateau region during first charge in high-capacity lithium-rich layered oxide Li1.2Mn0.6Ni0.2O2 reversible capacity subsequent charge–discharge cycles has been systematically investigated. samples were synthesized by firing a sol–gel precursor obtained at 450 °C various temperatures (850–1000 °C) for 24 h optimum 900 6–72 h. maximum and, consequently achieved with sample fired In contrast, 1000 does not show any...

Owing to the sluggish kinetics of hydrogen oxidation reaction (HOR) in alkaline electrolyte, it is considered a limiting for development anion-exchange membrane fuel cell (AEMFC) technology. Studies HOR catalysis mainly focus on carbon-supported nanoparticles, which have weak metal–support interactions. In this contribution, we present unique support based transition metal carbides (TMCs = Mo2C, Mo2C–TaC, and Mo2C–W2C) HOR. PtRu nanoparticles are deposited onto TMC supports characterized by...

Abstract Graphene‐based materials have attracted significant attention in many technological fields, but scaling up graphene‐based technologies still faces substantial challenges. High‐throughput top‐down methods generally require hazardous, toxic, and high‐boiling‐point solvents. Here, an efficient inexpensive strategy is proposed to produce graphene dispersions by liquid‐phase exfoliation (LPE) through a combination of shear‐mixing (SM) tip sonication (TS) techniques, yielding highly...

Abstract Advanced lithium‐ion batteries (LIBs) are crucial to portable devices and electric vehicles. However, it is still challenging further develop the current anodic materials such as graphite due intrinsic limited capacity sluggish Li‐ion diffusion. Indium nitride (InN), which a new type of material with low redox potential (<0.7 V vs Li/Li + ) narrow bandgap (0.69 eV), may serve high‐energy density anode for LIBs. Here, growth 1D single crystalline InN nanowires reported on...

Large area microdomain alignment in a ferroelectric liquid crystalline diblock copolymer (LCBCP) poly(styrene)-block-poly(isoprene-LC), (PS−PILC), incorporating biphenyl 3-nitro-4-alkoxy-benzoate LC mesogenic group and non-LC block hexagonally packed cylinder microstructure, was successfully accomplished by application of magnetic field at elevated temperatures. Small- medium-angle X-ray scattering demonstrated that the PS cylinders matrix orient over large areas with their long axes...

Graphite oxide (GO) was discovered to catalyze the ring opening polymerization of various cyclic lactones and lactams, such as ε-caprolactone, δ-valerolactone, ε-caprolactam, their corresponding polyesters or polyamides. The resulting polymers were obtained in moderate number average molecular weights (4.8–12.8 kDa) good excellent yields (39–100%) at GO loadings ranging from 2.5–20.0 wt%. Using powder X-ray diffraction (PXRD) transmission electron microscopy (TEM), it determined that carbon...