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Developing high-efficiency and low-cost electrocatalyst is significant for the application of water splitting technology. Herein, Co3O4 nanoparticles and MnO2 nanosheets are separately synthesized and subsequently assembled into a unique 0/2-dimensional heterostructure via van der Waals interactions. The consequent composites expose abundant accessible active sites and expedite the reaction kinetics, which can be testified by the superiorities in Tafel slope, exchange current density and double-layer capacitance, only requiring overpotentials of 355 and 129 mV for oxygen and hydrogen evolution reactions in 1.0 M KOH at 10 mA cm−2, respectively. Moreover, a cell voltage of 1.660 V can drive the electrolyzer at 10 mA cm−2. Benefitted from robust integration, the original aggregation and restacking of individual materials have been overcome, thereby leading to superior elelctrocatalysis durability. This facile and universal strategy may inspire the researchers on the design and construction of advanced functional composites.

As one of the most abundant materials on earth, SiO2 has a broad prospect in the application of lithium ion batteries due to its high specific capacity, low cost and environmental friendliness. However, the low electrical conductivity and large volume variation during charging and discharging lead to the serious performance degradation of SiO2. In this paper, we synthesized a 1/2D hierarchical material, in which SiO2 nanotubes were uniformly anchored on the surface of reduced graphene oxide through electrostatic self-assembly, and it delivers a high discharge capacity of 961 mAh g−1 at the current density of 200 mA g−1 after 250 cycles. At a high current density of 5000 mA g−1, it still shows a decent discharge capacity of 378 mAh g−1 after 2000 cycles, drawing parallels to that of commercial graphite. The excellent performance is mainly attributed to the nanotube structure of SiO2 and its uniform distribution on rGO by electrostatic self-assembly.

Lithium–sulfur (Li–S) batteries face a few vital issues, including poor conductivity, severe volume expansion/contraction, and especially the detrimental shuttle effect during the long-term electrochemical process. Herein, we designed a hierarchical MXene@TiO2 nanoarray via in situ solvothermal strategies followed by heat treatment. The MXene@TiO2 heterostructure achieves superior charge transfer and sulfur encapsulation. Based on the polar–polar and Lewis acid–base mechanism, the robust dual chemisorption capability to trap polysulfides can be synergistically realized through the intense polarity of TiO2 and the abundant acid metal sites of MXene. Hence, the MXene@TiO2 nanoarray as a sulfur host retains a substantially stable discharge capacity of 612.7 mA h g−1 after 500 cycles at a rate of 2 C, which represents a low fading rate of 0.058% per cycle.

Lithium–sulfur (Li–S) batteries are regarded as one of the most promising candidates for next-generation energy storage systems due to their advantages of its high specific capacity and low material cost. Regrettably, the electrical insulation nature of sulfur, the volume expansion during lithiation, and the internal shuttle effect aroused by the polysulfides dissolution are the central issues for sulfur cathodes. Here, CoFe2O4@C nanocages derived from Prussian blue analogues and polydopamine were utilized as a sulfur host to address these problems. The polar Co–Fe oxide afforded chemical adsorption sites for anchoring polysulfides to reduce the shuttling effect. The hollow core structure of the nanocages could withstand the large volume change during lithiation and delithiation processes. The conductive carbon layer on the nanocages could ameliorate the extremely low electrical conductivity of S and Li2S. The S/CoFe2O4@C cathode demonstrated high capacity and excellent cyclability (821 mA h g−1 after 100 cycles at 0.5C). More importantly, the combinational strategies of good conductivity, physical space encapsulation, and chemical adsorption provide a means of resolving the current cathode issues in Li–S batteries.

In this communication, we report a general way to fabricate composite films comprising MXene nanosheets sandwiched by transition metal dichalcogenides/oxides, e.g., MoS2 nanotubes and MnO2 nanowires, through vacuum-assisted alternate filtration. The resulting MXene/MoS2 and MXene/MnO2 composite films can serve as flexible film anodes, and exhibit excellent lithium storage performance.

In order to get the low transmission rate in both mid infrared atmospheric window and far infrared atmospheric window, an infrared frequency selective surface composed of two layers based on hexagonal ring structure was designed. Simulation analysis using CST electromagnetic software shown that the frequency selective surface had two stopbands in both 3μm~5μm and 8μm~15μm regions, of which the average transmittance is lower than 2.5%. Therefore, this frequency selective surface realized two stopbands in infrared wavebands; This paper analyzed the filtering mechanism of the frequency selective surface based on the effective medium theory. In the end, this paper researched the effect of electromagnetic wave polarization mode, incident angle and dielectric layer thickness on the transmission properties of the frequency selective surface. The results revealed that the transmission of frequency selective surface is insensitive to polarization mode and incident angle, while the dielectric layer thickness is an important factor to the transmittance of frequency selective surface.

Novel dandelion-like Co3O4 mesoporous nanostructures, supported by a Cu foam, are prepared by a combination of hydrothermal synthesis and annealing. The resulting Co3O4@Cu foam exhibits superior oxygen evolution (Tafel slope = 42.8 mV dec-1) and lithium storage (capacity = 882 mA h g-1@2C after 100 cycles, 1C = 890 mA g-1) properties, which highlight its great promise in the fields of energy storage and conversion.

Electrocatalytic nitrogen reduction reaction is increasingly deemed as a promising route for massive ammonia synthesis. Herein, hollow bimetallic CoFe2O4 nanocube derived from prussian blue analogue is elaborately wrapped by thin carbon layer and modified by rich oxygen vacancies, achieving splendid ammonia yield rate of 30.97 μg h−1 mgcat.−1 and Faradaic efficiency of 11.65 % at −0.4 V versus reversible hydrogen electrode in 0.1 M Na2SO4. In addition, C@CoFe2O4-x nanocube can withstand long-term and repetitive electrolysis without obvious structure collapse, constituent change and activity decay. The prominent activity is strongly associated with improved nitrogen adsorption and activation, collaboratively benefiting from the intrinsic unoccupied d orbitals of transition metal components, reformative electronic structure by oxygen vacancies and elevated electron injection possibility into the antibonding orbital of nitrogen molecule via conductive carbon wrapper. Both actual experiments and theoretical investigations attest the catalytic activity improvement mechanism, rendering the C@CoFe2O4-x nanocube design strategy efficient and valid.

Lithium-sulfur (Li-S) batteries are generally considered as potential candidates for sustainable energy storage systems owing to low cost and high theoretical energy storage capability. However, the actual implementation of sulfur cathode in Li-S batteries is seriously hampered by the undesirable shuttle effect of lithium polysulfides (LiPS), inferior electroconductibility of S/Li2S and huge volume change during lithiation/delithiation process. Herein, the CoFe2O4 nanotubes decorated with polyaniline (PANI) are rationally designed and fabricated as efficient sulfur hosts to handle these challenges. Specifically, both CoFe2O4 and PANI components possess strong chemical affinity to the soluble intermediate LiPS. Meanwhile, from the perspective of structural superiority, the internal void space of nanotubes can effectively accommodate active sulfur particles and tolerate the large volume change upon cycling. Besides, the conductive polymer of PANI can greatly improve the cathode conductivity and facilitate the electron transfer for active materials. More importantly, the S/CoFe2O4@PANI electrode achieves excellent cycling performance with superior initial capacity of 864.1 mAh g−1 and good reversible capacity retention with 582.6 mAh g−1 even after 500 cycles at 2 C rate.

Tradition metal selenides have triggered extensive attentions in the field of electrochemical energy storage and conversion. Herein we propose a decent synergetic effect produced by delicate hybridization between exfoliated MoSe2 nanosheets and high conductive Ag nanoparticles (NPs) during self-assemble process. The Ag/MoSe2 hybrid architecture (weight ratio, 5:100) can reach 10 mA cm−2 current density at a potential as low as 0.187 V, which almost is ~3-fold lower than that for the bare MoSe2 nanosheets. Additionally, the Ag/MoSe2 hybrid architecture also exhibits an enhanced capacity, excellent rate abilities and superior cycling stability for lithium storage than pristine MoSe2 nanosheets. The comprehensive explorations of the synergistic effects occurring between MoSe2 nanosheets and Ag NPs have insights for the rational constructions of low cost electrocatalysts for hydrogen evolution as well as high performance electrode materials for lithium storage based on transition metal chalcogenides.

Here, we propose a multi-dimensionally hierarchical self-supported Cu@Cu2+1O@Co3O4 heterostructure as superior bifunctional material for lithium-ion storage and electrocatalytic oxygen evolution via rapid in-situ oxidation-electrodeposition-annealing treatment. The 3/1/2-dimensional hybridization heterostructure rationally organized by three-dimensional Cu foam, one-dimensional Cu2+1O nanowires and two-dimensional Co3O4 nanosheets achieves remarkable synergistic interactions. In brief, the free-standing Cu foam framework enables remarkable structure robustness, electronic conductivity and electrolyte infiltration. Meanwhile, the in-situ grown Cu2+1O nanowires with excess metal defects indeed provide certain activity, effectively adjust the size and distribution of anchored Co3O4 nanosheets and dramatically shorten the diffusion pathway of ions and electrons. Moreover, the constructed interfaces between Cu2+1O and Co3O4 further yield sufficient electrochemically active surface area. In consequence, Cu@Cu2+1O@Co3O4 heterostructure delivers superior lithium-ion storage capacity and electrocatalytic oxygen evolution activity. Specifically, a prominent and stable discharge capacity of 1090 mAh g−1 can be delivered after 200 cycles at 500 mA g−1. Even when the current density is elevated to 5000 mA g−1, remarkable discharge capacity of 601 mAh g−1 still can be yielded. As for the electrocatalytic oxygen evolution activity, Cu@Cu2+1O@Co3O4 heterostructure demonstrates a particularly low overpotential of 223 mV at 10 mA cm−2 and Tafel slope of 46.3 mV dec−1. This strategy may enlighten the researchers on the further development of electrochemically active materials for advanced electrode and catalyst.

To address the deficiencies of poor electronic conductivity and strong tendency towards aggregation suffered by V2O5 nanosheets, here we propose a facile and elegant self-organization strategy to decorate them simultaneously with Ag nanoparticles and TiO2 nanorods, resulting in novel two-dimensional hybrid architectures. The addition of TiO2 is able to enhance the Li+ intercalation rate and capacity of V2O5, while the introduction of Ag is capable of allowing for efficient electron transport from the current collector to the electrode. Moreover, the two dopants can effectively isolate the V2O5 nanosheets from restacking, thereby preserving the electroactive surface areas from being sacrificed. The resulting two-dimensional hybrid architectures exhibit synergistic superiorities in reversible capacity, rate capability and cycle stability over neat V2O5 nanosheets, and hold great promise as a cathode material of lithium-ion batteries.

MnO2, featured by an extremely high theoretical capacity (1230 mA h g−1), has recently been explored as a promising anode material for lithium-ion batteries (LIBs). Moreover, MnO2 in different nanostructures is particularly attractive because of shortened lithium diffusion pathways and increased active sites for lithium storage. However, nanostructured MnO2 still faces unsatisfactory cyclability, especially at high rates, due to a strong inclination to aggregate as well as a low intrinsic conductivity. Here we report a novel, delicate 1/2D hybrid architecture through an elaborate morphological design, by which SnO2 nanowires are hierarchically assembled on MnO2 nanosheets based on van der Waals interactions. The two building blocks, hand in hand, exhibit a remarkable synergy in reversible lithium storage. On the one hand, the large, flexible and elastic MnO2 nanosheets provide not only excellent electrochemical activities but also superior mechanical performances. On the other hand, the SnO2 nanowires, in addition to the substantial capacity contribution, play two other vital roles: (1) acting as a spacer to isolate the MnO2 nanosheets from restacking, thereby ensuring a large interlayer spacing for lithium diffusion; (2) serving as a conductive dopant to enable efficient, continuous one-way electron transport due to a high intrinsic conductivity. It is very encouraging to find that strikingly high reversible capacities and rate capabilities are delivered, ranking our 1/2D hybrid architecture as an advanced anode material for next-generation, high-power LIBs.

A novel 3D MoS2@Fe3O4 nanohybrid, composed of tubular MoS2 uniformly and densely decorated with particulate Fe3O4, is constructed, which exhibits significantly improved lithium storage performances through an impressive synergistic interplay between the two active materials.

The experiments were carried out in the paper to investigate the effect of adding hydrogen in titanium alloy TC4 on its machinability. The hydrogen contents selected were 0, 0.25%, 0.49%, 0.63%, 0.89% and 1.32%, respectively. Experiments with varing hydrogen contents and cutting conditions concurrently. Experimental results showed that the cutting force of the titanium alloy can be obviously reduced and the surface roughness can be improved by adding appropriate hydrogen in the material. In the given cutting condition, the titanium alloy TC4 with 0.49% hydrogen content showed better machinability.

The influence of β crystalline form nucleating agent (β nucleator) on the mechanical properties of homo-polymerized polypropylene (PPH), random-copolymerized polypropylene (PPR), block-copolymerized polypropylene (PPB), and PPH/PPR/PPB blends was studied. Polarized optical microscopy (POM), differential scanning calorimetry (DSC), and wide angle X-ray diffraction (WAXD) were used to characterize the crystalline morphology and behavior. The results indicated that α crystalline form of polypropylene (PP) had transformed to β crystalline form by adding 0.5% β nucleator; in the meantime, the toughness of PP and its blends was enhanced. That is, 0.5% β nucleator helped to improve the notched impact strength of PPH, PPR, and PPH/PPR/PPB blends by 130%, 40%, and 40%, respectively, without losing the tensile strength and flexural strength.