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For building high-energy density asymmetric supercapacitors, developing anode materials with large specific capacitance remains a great challenge. Although Fe2O3 has been considered as a promising anode material for asymmetric supercapacitors, the specific capacitance of the Fe2O3-based anodes is still low and cannot match that of cathodes in the full cells. In this work, a composite material with well dispersed Fe2O3 quantum dots (QDs, ≈2 nm) decorated on functionalized graphene-sheets (FGS) is prepared by a facile and scalable method. The Fe2O3 QDs/FGS composites exhibit a large specific capacitance up to 347 F g−1 in 1 m Na2SO4 between -1 and 0 V versus Ag/AgCl. An asymmetric supercapacitor operating at 2 V is fabricated using Fe2O3/FGS as anode and MnO2/FGS as cathode in 1 m Na2SO4 aqueous electrolyte. The Fe2O3/FGS//MnO2/FGS asymmetric supercapacitor shows a high energy density of 50.7 Wh kg−1 at a power density of 100 W kg−1 as well as excellent cycling stability and power capability. The facile synthesis method and superior supercapacitive performance of the Fe2O3 QDs/FGS composites make them promising as anode materials for high-performance asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]

Mesoporous ZnO-NiO architectures were prepared by thermal annealing of zinc-nickel hydroxycarbonate composites. The resulting architectures are shown to be assembled by many mesoporous nanosheets, and this results in a large surface area and a strong synergy between the ZnO and NiO nanoparticles. The material obtained by annealing at 400 °C was used as an electrode that responds to glucose over a wide concentration range (from 0.5 μM to 6.4 mM), with a detection limit as low as 0.5 μM, fast response time (<3 s), and good sensitivity (120.5 μA · mM · cm). [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Iron oxides are potential electrode materials for lithium-ion batteries because of their high theoretical capacities, low cost, rich resources, and their non-polluting properties. However, iron oxides demonstrate large volume expansion during the lithium intercalation process, resulting in the electrode material being crushed, which always results in poor cycle performance. In this paper, to solve the above problem, iron oxide/carbon nanocomposites with a hollow core–shell structure were designed. Firstly, an Fe2O3@polydopamine nanocomposite was prepared using an Fe2O3 nanocube and dopamine hydrochloride as precursors. Secondly, an Fe3O4@N-doped C composite was obtained by means of further carbonization treatment. Finally, Fe3O4@void@N-Doped C-x composites with core–shell structures with different void sizes were obtained by means of Fe3O4 etching. The effect of the etching time on the void size was studied. The electrochemical properties of the composites when used as lithium-ion battery materials were studied in more detail. The results showed that the sample that was obtained via etching for 5 h using 2 mol L−1 HCl solution at 30 °C demonstrated better electrochemical performance. The discharge capacity of the Fe3O4@void@N-Doped C-5 was able to reach up to 1222 mA g h−1 under 200 mA g−1 after 100 cycles. [ABSTRACT FROM AUTHOR]

A correction to the article "Ultrathin Nanobelts as an Excellent Bifunctional Oxygen Catalyst: Insight into the Subtle Changes in Structure and Synergistic Effects of Bimetallic Metal-Organic Framework," by Xiao Xiao, Qing Li, Xinya Yuan, Mingbo Zheng, and Huan Pang.

Carbon-coated Mn3O4 nanowires (Mn3O4@C NWs) have been synthesized by the reduction of well-shaped carbon-coated bixbyite networks and characterized by TEM, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical experiments. To assess the properties of 1D carbon-coated nanowires for their use in supercapacitors, cyclic voltammetry and galvanostatic charging-discharging measurements were performed. Mn3O4@C NWs could be charged and discharged faster and had higher capacitance than bare Mn3O4 nanostructures and other commercial materials. The capacitance of the Mn3O4@C NWs was 92 % retained after 3000 cycles at a charging rate of 5 A g−1. This improvement can be attributed to the carbon shells, which promote fast Faradaic charging and discharging of the interior Mn3O4 core and also act as barriers to protect the inner core. These Mn3O4@C NWs could be a promising candidate material for high-capacity, low-cost, and environmentally friendly electrodes for supercapacitors. In addition, the magnetic properties of the as-synthesized samples are also reported to investigate the influence of the carbon coating. [ABSTRACT FROM AUTHOR]

Abstract: High-density Co3O4 nanowire arrays have been fabricated by a simple, solvent-free synthesis method inside the alumina pores. It has been found that the pore diameter played a key role in the formation of the Co3O4 nanowires. When the same reaction was performed in the narrow pores of the AAO template (<90nm), a mixture of nanoparticles and short nanorods were obtained. The nanorod consists of a lot of obvious grains, which form grain chains. However, continuous and uniform nanowires could be produced when the larger pores of AAO (>120nm) were applied. Selected-area electron diffraction (SAED) patterns revealed that the nanowires were single-crystalline. Electrochemical measurements by an electrochemical workstation indicate that the specific capacitance characteristics of the as-prepared Co3O4 nanowires are much higher than that of Co3O4 particles. [Copyright &y& Elsevier]

Abstract: Cuspate deltoid cobaltous oxide (CoO) crystallites with an average grain size of 3μm were obtained via developing the Co3O4 nanoplatelets under the KCl/NaCl flux atmosphere. The as-synthesized products were characterized by powder X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscope and selected area electron diffraction. The electrochemical properties of the products were investigated by an Electrochemical Workstation device at room temperature. It has been found that the final prepared cubic CoO crystallites are of uniform cuspate deltoid morphology. The results of electrochemical tests indicate that the CoO shows acceptable capacitive behavior with specific capacitance about 88F/g. [Copyright &y& Elsevier]

Abstract: Shape-controlled synthesis of CuS nanorods, nanoflakes, and flowerlike structures has been achieved simply in the presence of a nonionic surfactant polyethylene glycol (PEG20000) by adjusting hydrothermal temperature. The as-synthesized CuS nanocrystals were investigated by various techniques of XRD, TEM, SEM, and UV–vis spectra. The electron diffraction pattern indicated that the CuS nanoflakes were single crystals. In the process, the temperature and the surfactant PEG20000 were found to play important roles in determining the morphology of CuS nanocrystals. [Copyright &y& Elsevier]

Abstract: By employing sodium dodecyl sulfate as the templating agent, mesoporous lanthanum oxide/surfactant complexes of hexagonal and lamellar phases were synthesized within the micellar solution of various pH values. The structures of the resulting products were studied by XRD, HRTEM, SEM and TG/DTA. The XRD patterns and HRTEM micrographs showed that the interlayer distance of the typical lamellar structure products was ranging from 3.5 to 4.0 nm and the unit cell parameter of the produced ordered hexagonal structures was about 4.4 nm. [Copyright &y& Elsevier]

Fe2O3 nanocrystals were uniformly anchored onto graphene nanosheets (Fe2O3@GNS) by a nanocasting technique, and the resulting composites were applied as anodes of sodium-ion batteries. Fe2O3@GNS exhibits excellent cycling performance and rate capability. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports a novel preparation of Mesostructure anatase TiO2 nanoparticles and monodisperse spheres with high surface area. In this synthesis we use 1-(2-hydroxylethyl)-3 -methylimidazolium based room temperature ionic liquids (RTILs) as solvents via the sol–gel method at low temperature. The product was analyzed and characterized by X-ray diffraction (XRD), Transmission electron microscope (TEM), Scanning electron microscope (SEM), N2 adsorption and desorption. The mechanism was also discussed. It was believed that the RTILs played an important role as a self-assembling template and the high surface area of the samples is thought to mainly attribute to the formation of mesopores with crystallinity in the reaction. [Copyright &y& Elsevier]

In recent years, increasing attention has been paid to metal–organic frameworks by scientists working in the field of electrocatalytic material chemistry. Herein, using the hydrothermal method, ultrathin Ni/Co bimetallic metal–organic framework nanobelts that can be directly adopted as highly efficient electrocatalysts are prepared. The optimized Ni/Co ultrathin nanobelts can reach an onset potential of 0.939 V [these values are very close to those of Pt/C (0.940 V)] and show superior stability relative to that of Pt/C toward oxygen reduction reaction (ORR). Additionally, under the current density of 10 mA cm−2, the Ni/Co ultrathin nanobelts show the potential of 1.478 V for oxygen evolution reaction (OER), which is much better than that of IrO2, indicating the large potential of the metal–organic frameworks as a bifunctional oxygen catalyst in metal–air batteries. In addition, after OER and ORR, the color of the Ni/Co ultrathin nanobelts sample is slightly lighter, and it can be seen that the channel becomes blurred but still exists. The X‐ray diffraction, infrared spectrometry, and X‐ray photoelectron spectroscopy results for Ni/Co ultrathin nanobelts before and after catalysis are basically identical. The findings suggest that the ultrathin belt‐like structure and the synergy effect between Ni and Co are crucial for tuning the electrocatalytic activity. Bimetallic ultrathin metal–organic framework nanobelts represent one kind of promising power materials for electrocatalytic material chemistry. Facile one‐step hydrothermal synthesis strategies, high electrocatalysis activity, and excellent stability are prominent features of oxygen reduction reaction and oxygen evolution reaction. The electrocatalysis activity of the metal–organic framework nanobelts can be adjusted by controlling the introduction of Co content. [ABSTRACT FROM AUTHOR]