Novel 3D Ni Co Se mesoporous nanosheet networks with tunable stoichiometry are successfully synthesized on Ni foam (Ni Co Se MNSN/NF with x ranging from 0 to 0.35). The collective effects of special morphological design and electronic structure engineering enable the integrated electrocatalyst to have very high activity for hydrogen evolution reaction (HER) and excellent stability in a wide pH range. Ni Co Se MNSN/NF is revealed to exhibit an overpotential (η ) of 85 mV at -10 mA cm in alkaline medium (pH 14) and η of 52 mV in acidic solution (pH 0), which are the best among all selenide-based electrocatalysts reported thus far. In particular, it is shown for the first time that the catalyst can work efficiently in neutral solution (pH 7) with a record η of 82 mV for all noble metal-free electrocatalysts ever reported. Based on theoretical calculations, it is further verified that the advanced all-pH HER activity of Ni Co Se is originated from the enhanced adsorption of both H and H O induced by the substitutional doping of cobalt at an optimal level. It is believed that the present work provides a valuable route for the design and synthesis of inexpensive and efficient all-pH HER electrocatalysts.

Diamonds have substantial hardness and durability, but attempting to deform diamonds usually results in brittle fracture. We demonstrate ultralarge, fully reversible elastic deformation of nanoscale (~300 nanometers) single-crystalline and polycrystalline diamond needles. For single-crystalline diamond, the maximum tensile strains (up to 9%) approached the theoretical elastic limit, and the corresponding maximum tensile stress reached ~89 to 98 gigapascals. After combining systematic computational simulations and characterization of pre- and postdeformation structural features, we ascribe the concurrent high strength and large elastic strain to the paucity of defects in the small-volume diamond nanoneedles and to the relatively smooth surfaces compared with those of microscale and larger specimens. The discovery offers the potential for new applications through optimized design of diamond nanostructure, geometry, elastic strains, and physical properties.

NiO nanoflakes are created with a simple hydrothermal method on 3D (three‐dimensional) graphene scaffolds grown on Ni foams by microwave plasma enhanced chemical vapor deposition (MPCVD). Such as‐grown NiO‐3D graphene hierarchical composites are then applied as monolithic electrodes for a pseudo‐supercapacitor application without needing binders or metal‐based current collectors. Electrochemical measurements impart that the hierarchical NiO‐3D graphene composite delivers a high specific capacitance of ≈1829 F g−1 at a current density of 3 A g−1 (the theoretical capacitance of NiO is 2584 F g−1). Furthermore, a full‐cell is realized with an energy density of 138 Wh kg−1 at a power density of 5.25 kW kg−1, which is much superior to commercial ones as well as reported devices in asymmetric capacitors of NiO. More attractively, this asymmetric supercapacitor exhibits capacitance retention of 85% after 5000 cycles relative to the initial value of the 1st cycle.

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The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections.

We present the design and synthesis of three-dimensional (3D)-networked NiCo 2 S 4 nanosheet arrays (NSAs) grown on carbon cloth along with their novel application as anodes in lithium-ion batteries. The relatively small (~60%) volumetric expansion of NiCo 2 S 4 nanosheets during the lithiation process was confirmed by in situ transmission electron microscopy and is attributed to their mesoporous nature. The 3D network structure of NiCo 2 S 4 nanosheets offers the additional advantages of large surface area, efficient electron and ion transport capability, easy access of electrolyte to the electrode surface, sufficient void space and mechanical robustness. The fabricated electrodes exhibited outstanding lithium-storage performance including high specific capacity, excellent cycling stability and high rate of performance. A reversible capacity of~1275 mAh g − 1 was obtained at a current density of 1000 mA g − 1 , and the devices retained~1137 mAh g − 1 after 100 cycles, which is the highest value reported to date for electrodes made of metal sulfide nanostructures or their composites. Our results suggest that 3D-networked NiCo 2 S 4 NSA/carbon cloth composites are a promising material for electrodes in high-performance lithium-ion batteries. INTRODUCTIONRechargeable lithium-ion batteries (LIBs) are the most widely used electrochemical energy storage devices because of their inherent advantages including high energy density, long life span, lack of memory effect and environmental nontoxicity. 1-3 The increasing applications of LIBs in daily electronic devices-along with industry demands for further improvement in energy density, durability, rate capability and safety-have driven the development of new electrode materials and new electrode structures. [4][5][6][7] Among the great variety of anode materials studied, metal oxides (MOs) and metal sulfides ( 21 have been synthesized and offer superior electrochemical energy storage capacity compared with bulk MSs. However, the large volumetric change of MS nanostructures during electrochemical reactions leads to reduced capacity and poor cycling stability. Moreover, the necessary addition of conductive additives and binders inevitably lessens overall energy

A scalable, green method to prepare microporous carbon from sugarcane waste for superior lithium storage capability of Fe1−xS.

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