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Lithium-sulfur (Li-S) batteries suffer from multiple complex and often interwoven issues, such as the low electronic conductivity of sulfur and Li2S/Li2S2, shuttle effect, and sluggish electrochemical kinetics of lithium polysulfides (LiPSs). Guided by theoretical calculations, a multifunctional catalyst of isolated single-atom nickel in an optimal Ni-N5 active moiety incorporated in hollow nitrogen-doped porous carbon (Ni-N5/HNPC) is constructed and acts as an ideal host for a sulfur cathode. The host improved electrical conductivity, enhanced physical-chemical dual restricting capability toward LiPSs, and, more importantly, boosted the redox reaction kinetics by the Ni-N5 active moiety. Therefore, the Ni-N5/HNPC/S cathode exhibits superior rate performance, long-term cycling stability, and good areal capacity at high sulfur loading. This work highlights the important role of the coordination number of active centers in single-atom catalysts and provides a strategy to design a hollow nanoarchitecture with single-atom active sites for high-performance Li-S batteries.

An Fe-N-C catalyst with an FeN

Developing an efficient catalyst for the electrocatalytic CO2 reduction reaction (CO2RR) is highly desired because of environmental and energy issues. Herein, we report a single-atomic-site Cu catalyst supported by a Lewis acid for electrocatalytic CO2 reduction to CH4. Theoretical calculations suggested that Lewis acid sites in metal oxides (e.g., Al2O3, Cr2O3) can regulate the electronic structure of Cu atoms by optimizing intermediate absorption to promote CO2 methanation. Based on these theoretical results, ultrathin porous Al2O3 with enriched Lewis acid sites was explored as an anchor for Cu single atoms; this modification achieved a faradaic efficiency (FE) of 62% at -1.2 V (vs RHE) with a corresponding current density of 153.0 mA cm-2 for CH4 formation. This work demonstrates an effective strategy for tailoring the electronic structure of Cu single atoms for the highly efficient reduction of CO2 into CH4.

Herein, we report efficient single copper atom catalysts that consist of dense atomic Cu sites dispersed on a three-dimensional carbon matrix with highly enhanced mesoporous structures and improved active site accessibility (Cu-SA/NC(meso)). The ratio of +1 to +2 oxidation state of the Cu sites in the Cu-SA/NC(meso) catalysts can be controlled by varying the urea content in the adsorption precursor, and the activity for ORR increases with the addition of Cu

Oxygen-involved electrochemical reactions are crucial for plenty of energy conversion techniques. Herein, we rationally designed a carbon-based Mn-N2C2 bifunctional electrocatalyst. It exhibits a half-wave potential of 0.915 V versus reversible hydrogen electrode for oxygen reduction reaction (ORR), and the overpotential is 350 mV at 10 mA cm-2 during oxygen evolution reaction (OER) in alkaline condition. Furthermore, by means of operando X-ray absorption fine structure measurements, we reveal that the bond-length-extended Mn2+-N2C2 atomic interface sites act as active centers during the ORR process, while the bond-length-shortened high-valence Mn4+-N2C2 moieties serve as the catalytic sites for OER, which is consistent with the density functional theory results. The atomic and electronic synergistic effects for the isolated Mn sites and the carbon support play a critical role to promote the oxygen-involved catalytic performance, by regulating the reaction free energy of intermediate adsorption. Our results give an atomic interface strategy for nonprecious bifunctional single-atom electrocatalysts.

Designing low-cost, high-efficiency, platinum-free electrocatalysts for the hydrogen oxidation reaction (HOR) in an alkaline electrolyte is of great importance for the development of anion exchange membrane fuel cells. Herein, we report a novel HOR catalyst, RuNi1, in which Ni is atomically dispersed on the Ru nanocrystals. To note, the as-prepared RuNi1 catalyst exhibits excellent catalytic activity and stability for HOR in alkaline media, which is superior to those of Ru-Ni bimetallic nanocrystals, pristine Ru, and commercial Pt/C catalysts. Density functional theory (DFT) calculations suggest that isolation of Ni atoms on Ru nanocrystals not only optimizes the hydrogen-binding energy but also decreases the free energy of water formation, thus leading to excellent electrocatalytic activity of RuNi1 catalyst. The results show that engineering a catalyst at an atomic level is highly effective for rational design of electrocatalysts with high performance.

Lithium-sulfur (Li-S) batteries suffer from multiple complex and often interwoven issues, such as the low electronic conductivity of sulfur and Li

Developing an efficient catalyst for the electrocatalytic CO

Oxygen-involved electrochemical reactions are crucial for plenty of energy conversion techniques. Herein, we rationally designed a carbon-based Mn-N

Functional fabrics with various unique properties are necessary for making fantastic superior costumes just like a superhero suit in Marvel Comics, which are not only dreams of boys but also emerging textiles to facilitate human life. On the basis of the inspiration of a phenomenon in an extracurricular experiment for kids, we develop a biofabrication strategy to endow silk textiles with various unique physical and chemical properties of functional nanomaterials, where the functional textiles are weaved using silk spun by silkworms that are fed with functional nanomaterials. To confirm the feasibility of this strategy, a photoluminescent plain weave was prepared successfully via feeding biocompatible luminescent nanoparticles to Bombyx mori silkworms. As the functional nanomaterials are enclosed in the silkfibers, the given special properties will be permanent for further application. Considering the wondrous diversity of properties that a variety of nanomaterials possesses may be given to silk fabric, it is promising to see various miraculous costumes in the coming future.

We report a facile, solution-phase route to large-scale fabrication and characterization of single crystalline Cu2O nanowires with controllable diameter, different morphologies, and high aspect ratios. The synthesis of Cu2O nanowires is achieved by the reduction of cupric acetate with o-anisidine, pyrrole, or 2,5-dimethoxyaniline under hydrothermal conditions. The electrical properties of individual Cu2O nanowires have been examined by I−V characteristics. The output properties of Cu2O/poly(2,5-dimethoxyaniline) core/shell nanowires show n-type characteristics and improved conductivity, while those of Cu2O nanowires are linear. The results from this study provide a low-cost, naturally abundant nanostructured material for use in electronic devices.

A facile wet chemical synthesis method was used to prepare a range of single-crystal Na(Y1.5 Na0.5)F6 nanorods with controllable aspect ratios. Their novel multicolor upconversion (UC) fluorescence has been successfully realized by doping Yb3+/Er3+ (green) and Yb3+/Tm3+ (blue) ion pairs. When doped with Eu3+ and Tb3+ ions, the strong red and green downconversion (DC) fluorescence has also been observed, respectively. Being covered with oleic acids, these luminescent nanorods have been transparently dispersed in nonpolar solvent. For their unique luminescence and controllable morphology and surface properties, these nanorods may find great applications in the fields of color displays, biolabels, light-emitting diodes (LEDs), optical storage, optoelectronics, anticounterfeiting, and solid-state lasers.

To exploit the novel size-dependent mechanical properties of nanowires, it is necessary for one to develop strategies to control the strength and toughness of these materials. Here, we report on the mechanical properties of silver nanowires with a unique fivefold twin structure using a lateral force atomic force microscopy (AFM) method in which wires are held in a double-clamped beam configuration. Force-displacement curves exhibit super elastic behavior followed by unexpected brittle failure without significant plastic deformation. Thermal annealing resulted in a gradual transition to weaker, more ductile materials associated with the elimination of the twinned boundary structure. These results point to the critical roles of microstructure and confinement in engineering the mechanical properties of nanoscale materials.

We report the crystal orientation tuning of LiFePO(4) nanoplates for high rate lithium battery cathode materials. Olivine LiFePO(4) nanoplates can be easily prepared by glycol-based solvothermal process, and the largest crystallographic facet of the LiFePO(4) nanoplates, as well as so-caused electrochemical performances, can be tuned by the mixing procedure of starting materials. LiFePO(4) nanoplates with crystal orientation along the ac facet and bc facet present similar reversible capacities of around 160 mAh g(-1) at 0.1, 0.5, and 1 C-rates but quite different ones at high C-rates. The former delivers 156 mAh g(-1) and 148 mAh g(-1) at 5 C-rate and 10 C-rate, respectively, while the latter delivers 132 mAh g(-1) and only 28 mAh g(-1) at 5 C-rate and 10 C-rate, respectively, demonstrating that the crystal orientation plays important role for the performance of LiFePO(4) nanoplates. This paves a facile way to prepare high performance LiFePO(4) nanoplate cathode material for lithium ion batteries.

Superaligned carbon nanotube (CNT) yarn patterned substrates were developed as the topographic scaffold for guiding the neurite outgrowth. As-prepared patterned substrates were used for culturing rat hippocampal neurons, without purifying and functionalizing processes on the CNTs. The neurite outgrowth on the patterned substrate exhibited a strong tendency to being aligned along the CNT yarns long axes. The neurite grown along the CNT yarns had much less branching than the one on a uniform planar substrate typically used for neuron culture. These results indicate that the pure CNT yarns possess the main characteristics of a guidance scaffold for neurite outgrowth. Furthermore, the CNT yarns can be mass produced and be easily weaved into desired structures, which may make them attractive for neuronal regeneration and tissue engineering.

Spin-dependent electron transport in individual magnetite (Fe3O4) nanowires contacted with normal metallic electrodes was investigated. Such a configured device demonstrated a spin-filter effect, that is, only the minority spin carriers can transport through the magnetite nanowire due to its negative spin polarization. An anomalous positive magnetoresistance approximately 7.5% is observed at room temperature. Moreover, the magnetoresistance can be controlled via bias voltage.