查看更多>>摘要：Hierarchically three-dimensional(3D)materials present a pivotal challenge and opportunity in achiev-ing effective microwave absorption with synergistic effects.In this work,α-Fe2O3@ZrO2 with core-shell structure were fabricated in-situ on aramid nanofibers by a solvothermal method.Following calcination,3D ZrO2/Fe3O4/C nanocomposites with Janus structure have been successfully synthesized.By control-ling the lattice match and mismatch in both processes,a core-shell structure of α-Fe2O3@ZrO2 and Janus structure of ZrO2/Fe3O4 have been well-define performed.The composite material ZrO2/Fe3O4/C-700 has a minimum reflection loss(RLmin)of-67.4 dB at a thickness of 2.0 mm.The effective absorption band-width(EAB)at a thickness of 2.4 mm is 6.0 GHz(11.0-17.0 GHz).This study provides a novel strategy for fabricating high-efficiency electromagnetic wave absorption materials with dual synergistic effects in nanosized scale.
查看更多>>摘要：Due to their potential use in creating advanced electronic textiles for wearable technology,functional fibers have garnered enormous interests.The presence of stretchable smart fibers has significantly ex-panded the application scenarios of intelligent fibers.However,preparing fibers that possess both ex-cellent electrical performance and high stretchability remains a formidable challenge.The fabrication of stretchable multifunctional fiber-based sensors employing a scalable method is reported here.Using a thermal drawing process,the collaborative interplay between the hollow confined channels of superelas-tic poly(styrene-b-(ethylene-co-butylene)-b-styrene)(SEBS)thermally drawn fibers and the high fluidity of liquid metal(LM)ensures the exceptional electrical performance of the fibers.Simultaneously,the presence of a helical structure further enhances both the sensing and mechanical properties.The helical two LM channel fiber-based sensors are capable of displaying more than 1000％strain,high stability over 1000 cycles,a quick pressure response and release time of 30.45 and 45.35 ms,and outstanding electrical conductivity of 8.075 x 105 S/m.In addition,the electrical conductivity of this fiber increases with strain level,reaching 3 × 106 S/m when the strain is 500％.Furthermore,due to their superior tension and compression sensing capabilities,flexible helical sensors offer considerable potential for use in wearable electronics applications such as human motion detection,Morse code compilation,multichannel sensing,and more.
查看更多>>摘要：This study ingeniously synthesized a novel CdS/NiS hollow nanoflower sphere(HNS)using a one-step method to enhance photocatalytic hydrogen production activity.Compared to conventional preparation methods,this approach features seamlessly interfaced contact that facilitates efficient electron transfer across the interface.The internal hollow structure allows for multiple light reflections,maximizing light absorption,while the exterior shell and inner surfaces simultaneously offer active sites for reactions.The modification with non-noble metal NiS enables the extraction of electrons from CdS to the NiS surface,achieving rapid charge separation.Furthermore,adsorption-free energy calculations reveal that the NiS surface is more conducive to photocatalytic hydrogen generation,providing additional reaction active sites.The results demonstrate a hydrogen production rate of 2.18 mmol g-1 h-1 for CdS/NiS HNS,which is 9.48 times greater than that of pristine CdS.This work presents a novel approach for synthesizing seamlessly interfaced contacts between photocatalysts and cocatalysts,offering new insight into efficient one-step synthesis for enhanced photocatalytic performance.
查看更多>>摘要：Coupling metal-organic frameworks(MOFs)with inorganic semiconductors to construct S-scheme hetero-junction photocatalysts is an effective way to facilitate photocarriers transfer and separation,as well as enhance redox ability for photocatalytic water-splitting into H2.However,the poor electrical conductiv-ity of MOFs,fast recombination of photogenerated electron-hole pairs,and slow surface redox reaction rates on photocatalysts lead to inefficient consumption of all charge carriers thus impeding further im-provement of photocatalytic activity.Thus,optimizing the separation,transfer,and utilization efficiencies of interfacial charge carriers in MOFs-based S-scheme heterojunction may pave the way for achieving excellent photocatalytic activity.Herein,a novel Schottky-assisted S-scheme heterojunction photocata-lyst CdS/Pt@NU-1000 was prepared by the combination of Pt-embedded NU-1000 with CdS.The opti-mized photocatalyst CdS/0.7Pt@NU-1000 exhibits the highest visible-light-driven H2 evolution rate with 3.604 mmol g-1 h-1,which is 12.7 and 18.8 folds of that for single CdS and NU-1000,respectively.The splendid photocatalytic performance benefited from the broadened light absorption,and the synergis-tic effect of the formed Schottky junction and S-scheme heterojunction.Furthermore,the formation of the S-scheme system was validated by density functional theory(DFT)calculations,in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS),and electron paramagnetic resonance(EPR)test.This work can provide some guidance for the design of efficient heterojunction photocatalysts by optimizing interfacial charge transfer.
查看更多>>摘要：The transformation of Li2S2-Li2S is indubitably the most crucial and labored rate-limiting step among the sophisticated reactions for the lithium-sulfur batteries(LSBs),the adjustment of which is anticipated to impede the shuttle effect.Herein,a N,Se dual-doped carbon nanocages embedded by Co-CoSe2 nanopar-ticles(Co-CoSe2@NSeC)is employed as a functional coating layer on commercial separator to improve the performance of LSBs.The well-designed N,Se co-doped nanostructures endow the modified layer with a satisfactory capacity for blocking polysulfides.Both calculations and experiments jointly disclose that the Li2S2 to Li2S reaction,including the liquid-solid conversion,was prominently expedited both thermodynamically and electrodynamically.Consequently,the batteries fabricated with Co-CoSe2@NSeC modified separator can deliver a favorable 764.2 mAh g-1 with 8.0 C,accompanied by a salient long cy-cling lifespan(only 0.066％at 1 C and 0.061％under 2 C after 1000 and 2000 cycles),and a desired anode protection.In addition,despite a raised areal loading of 7.53 mg cm-2 was introduced,the cells assembled by Co-CoSe2@NSeC@PP are allowed to produce an outstanding initial behavior of 8.71 mAh cm-2 under 0.2 C.This work may reinforce further explorations and serve with valuable insights into N,Se dual-doping materials for high-performance LSBs.
查看更多>>摘要：The influence of minor Ag on the precipitation evolution of the Al-4.2Zn-2.8Mg-1.0Cu(wt.％)alloy from early stages to over-aged stages at 150 ℃ was investigated.Surprisingly,co-precipitation of strengthening phases T'and η'are found in both Ag-free and Ag-added alloys.With Ag addition,precipitation of both T'and η'is refined and increased,such that the age-hardening capabilities and peak-aged tensile strength are improved.In addition,the quantitative proportion of η'precipitates increases with the increase of Ag content due to the increase in the(Zn+Cu)/Mg ratio of nucleating particles.The narrowed precipitate-free zones(PFZs)are considered responsible for the undiminished fracture elongation in Ag-added alloys.Essentially,these effects of Ag are closely related to the strong Ag-vacancy and Ag-solute interactions.In over-aged stages,the Ag-added alloys still possess higher hardness values compared to the Ag-free al-loy,which is related to precipitate coarsening mechanisms.The Ag-free alloy follows classical coarsening behavior by solid solution mediated diffusion,while the Ag-added alloy follows two possible coarsen-ing mechanisms,coalescence of aggregates and diffusion of atoms.The smaller average size and higher residual number density of precipitates benefited from the slow diffusion-controlled coarsening behavior depending on the precipitate composition characteristics of the two-stage differentiation and the precip-itate distribution characteristics of high-density dispersion in early-aged stages could explain why the hardness of Ag-added alloy keeps at a higher level than that of Ag-free alloy even after 1000 h ageing.Meanwhile,the transformation of metastable phases to stable phases is inhibited due to the addition of Ag,such that GP zones,T',η',η and T phases coexist even after 14 d of ageing.In terms of phase com-position,the addition of Ag decreases the ratio of Mg/(Al+Zn)in T-type phase.For the Ag-added alloy,the sum concentration of Zn+Mg in η'phase is about 10 at.％higher compared to T'phase,and η phase continues to have a high sum concentration of Zn+Mg,besides,the Zn/Mg ratio and Cu concentration exhibit obvious differences from T phase.
查看更多>>摘要：Highly sensitive sensors with extensive applications are extremely desired in the next-generation wear-able electronics for human motion monitoring,human-machine interface and intelligent robotics,while single-functional pressure sensors cannot fulfill the growing demands of modern technological advances.Herein,an all-fabric and multilayered piezoresistive sensor based on conductive metal-organic frame-work/layered double hydroxide(cMOF/LDH)hetero-nanoforest is demonstrated to achieve multiple ap-plications including pulse detection,joint motion detection,sound detection and information transmis-sion.Benefiting from the synergism of cMOF/LDH hetero-nanoforest and multilayered structure,the sen-sor exhibits a high sensitivity(1.61 × 109 kPa-1)over a broad pressure range(0-100 kPa),a fast re-sponse/recovery time(71 ms/71 ms)and a low detection limit(18 Pa),as well as reliable dynamic sta-bility(8000 cycles).It is gratifying to note that the introduction of cMOFs endows the sensor with the potential to detect the concentration of NH3(1-100 ppm)and sunlight intensity(10-100 mW cm-2).This work shows great potential in multifunctional sensing,which enlightens a strategy for advancing the development process of highly sensitive intelligent wearable devices.
查看更多>>摘要：The electropulsing process can be used to tailor the microstructure and deformability of metallic glasses(MGs).Here,we report the microstructural origin of enhanced electroplasticity of monatomic Ta MG nanowires.Under electromechanical loading,the Ta MG nanowire exhibits improved ductility and ob-vious necking behavior.By evaluating the dynamic structural evolution via in situ diffraction,it is found that the atomic mobility in flow units of Ta MG can be improved significantly under the stimulation of pulse current,mainly through the athermal electron-atom interaction,which results in the fast annihila-tion of flow units and,thereby,fast structural relaxation.These structural evolution processes can help to eliminate the formation of the obvious shear band.These findings provide insight into the origin of elec-troplasticity in amorphous materials,which is of scientific and technological significance for the design and processing of a variety of MGs.
查看更多>>摘要：Compared with traditional hydrogen storage alloys,perovskite oxide LaFeO3 materials are considered as one of the most promising anode materials for nickel-metal hydride batteries owing to their low cost,environmental friendliness,and superior temperature resistance.However,the biggest problem faced by perovskite oxide LaFeO3 as an anode material for Nickel/metal hydride(Ni-MH)batteries is the low elec-trical conductivity and poor specific capacity,which is mainly due to the serious agglomeration phe-nomenon in its structure.To solve the above problems,lamellar LaFeO3 material with large specific sur-face area and small particle size has been synthesized by adding N,N-Dimethylformamide(DMF)and polyvinyl pyrrolidone(PVP)inhibitor materials to the precursor.By changing the sintering temperature,the lamellar composite LaFeO3 material can be controlled.Consequently,the maximum discharge capac-ity of lamellar LaFeO3 is up to 372.1 mA h g-1 at the discharge current density of 60 mA g-1.Meanwhile,after 100 cycles,the specific discharge capacity of the lamellar LaFeO3 can still reach 293.1 mA h g-1,which is much higher than that of 98.5 mA h g-1 for LaFeO3.In addition,the kinetics of LaFeO3 has been investigated and the lamellar LaFeO3 shows excellent dynamic properties.Notably,the exchange current density I0(300 mA g-1)of the layered LaFeO3 electrode is higher than that of LaFeO3(150 mA g-1).Over-all,this work provides insights into a structure-performance relationship for the further development of high-performance perovskite-type oxide nickel-metal hydride battery anodes.
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