The current study is directed to the rapidly developing field of inorganic material 3D object production at nano-/micro scale.The fabrication method includes laser lithography of hybrid organic-inorganic materials wit...The current study is directed to the rapidly developing field of inorganic material 3D object production at nano-/micro scale.The fabrication method includes laser lithography of hybrid organic-inorganic materials with subsequent heat treatment leading to a variety of crystalline phases in 3D structures.In this work,it was examined a series of organometallic polymer precursors with different silicon(Si)and zirconium(Zr)molar ratios,ranging from 9:1 to 5:5,prepared via sol-gel method.All mixtures were examined for perspective to be used in 3D laser manufacturing by fabricating nano-and micro-feature sized structures.Their spatial downscaling and surface morphology were evaluated depending on chemical composition and crystallographic phase.The appearance of a crystalline phase was proven using single-crystal X-ray diffraction analysis,which revealed a lower crystallization temperature for microstructures compared to bulk materials.Fabricated 3D objects retained a complex geometry without any distortion after heat treatment up to 1400℃.Under the proper conditions,a wide variety of crystalline phases as well as zircon(ZrSiO_(4)-a highly stable material)can be observed.In addition,the highest new record of achieved resolution below 60 nm has been reached.The proposed preparation protocol can be used to manufacture micro/nano-devices with high precision and resistance to high temperature and aggressive environment.展开更多
Oxygen reduction reaction(ORR)is of significance for energy conversion technologies such as fuel cells and metal-air batteries[1,2].Currently,the electrocatalysts still need to employ expensive precious metal platinum...Oxygen reduction reaction(ORR)is of significance for energy conversion technologies such as fuel cells and metal-air batteries[1,2].Currently,the electrocatalysts still need to employ expensive precious metal platinum(Pt)as the main active component to overcome the sluggish kinetics of ORR[3,4].The exploration of low-cost.展开更多
Grain coalescence has been applied in many areas of nanofabrication technology, including modification of thinfilm properties, nanowelding, and self-assembly of nanostructures. However, very few systematic studies of ...Grain coalescence has been applied in many areas of nanofabrication technology, including modification of thinfilm properties, nanowelding, and self-assembly of nanostructures. However, very few systematic studies of selfassembly using the grain coalescence, especially for threedimensional(3D) nanostructures, exist at present. Here, we investigate the mechanism of plasma triggered grain coalescence to achieve the precise control of nanoscale phase and morphology of the grain coalescence induced by exothermic energy. Exothermic energy is generated through etching a silicon substrate via application of plasma. By tuning the plasma power and the flow rates of reactive gases, different etching rates and profiles can be achieved, resulting in various morphologies of grain coalescence. Balancing the isotropic/anisotropic substrate etching profile and the etching rate makes it possible to simultaneously release 2D nanostructures from the substrate and induce enough surface tension force,generated by grain coalescence, to form 3D nanostructures.Diverse morphologies of 3D nanostructures have been obtained by the grain coalescence, and a strategy to achieve self-assembly, resulting in desired 3D nanostructures, has been proposed and demonstrated.展开更多
The development of efficient electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) with excellent catalytic performance and stability plays key roles in the commercialization of wate...The development of efficient electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) with excellent catalytic performance and stability plays key roles in the commercialization of water splitting to generate hydrogen energy. Herein, a 2 D-3 D nanostructure composed of metal hydroxides and Prussian blue analogus(PBA) was in-situ decorated onto the Ni Fe foam(Pt-Ni Fe PBA) through a facile and scalable corrosive-coordinate approach. The specifically designed morphology favored the provision of abundant active sites, optimized the reaction pathway, and accelerated mass transport during the electrocatalytic process. Consequently, the as-synthesized Pt-Ni Fe PBA reached 10 m A cm^(-2) with small overpotentials of 29 and210 m V in 1 mol L;KOH deionized water for HER and OER,respectively. Remarkably, Pt-Ni Fe PBA required an overpotential of 21 m V to drive 10 m A cm^(-2) in seawater containing1 mol L;KOH with prominent durability. Moreover, with the as-synthesized Pt-Ni Fe PBA as bifunctional electrocatalyst,the Pt-Ni Fe PBA||Pt-Ni Fe PBA electrolyzer needed 1.46 and1.48 V to drive 10 m A cm^(-2) in 1 mol L;KOH with deionized water and 1 mol L;KOH with seawater, respectively. Remarkably, sustainable energies were utilized to power the overall water splitting and stored as easily portable hydrogen energy.展开更多
Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and...Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and energy applications.Recently,the construction of a step-scheme heterostructure system(hereafter called the S-scheme)has received widespread attention in the photocatalytic field due to its ability to achieve efficient photogenerated carrier separation and obtain strong photo-redox ability.Herein,a novel S-scheme heterojunction system consisting of 2D O-doped g-C_(3)N_(4)(OCN)nanosheets and 3D N-doped Nb_(2)O_(5)/C(N-NBO/C)nanoflowers is constructed via ultrasonication and vigorous agitation technique followed by heat treatment for the photocatalytic degradation of Rhodamine B(RhB).Detailed characterization and decomposition behaviour of RhB showed that the fabricated material shows excellent photocatalytic efficiency and stability towards RhB photodegradation under visible-light illumination.The enhanced performance could be attributed to the following factors:fast charge transfer,highly-efficient charge separation,extended lifetime of photoinduced charge carriers,and the high redox capability of the photoinduced charges in the S-scheme system.Various trapping experiment conditions and electron paramagnetic resonance provide clear evidence of the S-scheme photogenerated charge transfer path,meanwhile,the RhB mineralization degradation pathway was also investigated using LC-MS.This study presents an approach to constructing Nb_(2)O_(5)-based S-scheme heterojunctions for photocatalytic applications.展开更多
Structural DNA nanotechnology, an emerging technique that utilizes the nucleic acid molecule as generic polymer to programmably assemble well-defined and nano-sized architectures, holds great promise for new material ...Structural DNA nanotechnology, an emerging technique that utilizes the nucleic acid molecule as generic polymer to programmably assemble well-defined and nano-sized architectures, holds great promise for new material synthesis and constructing functional nanodevices for different purposes. In the past three decades, rapid development of this technique has enabled the syntheses of hundreds and thousands of DNA nanostructures with various morphologies at different scales and dimensions. Among them, discrete three-dimensional （3D） DNA nanostructures not only represent the most advances in new material design, but also can serve as an excellent platform for many important applications. With precise spatial addressability and capability of arbitrary control over size, shape, and function, these nanostructures have drawn particular interests to scientists in different research fields. In this review article, we will briefly summarize the development regarding the synthesis of discrete DNA 3D nanostructures with various size, shape, geometry, and topology, including our previous work and recent progress by other groups. In detail, three methods majorly used to synthesize the DNA 3D objects will be introduced accordingly. Additionally, the principle, design rule, as well as pros and cons of each method will be highlighted. As functions of these discrete 3D nanostructures have drawn great interests to researchers, we will further discuss their cutting-edge applications in different areas, ranging from novel material synthesis, new device fabrication, and biomedical applications, etc. Lastly, challenges and outlook of these promising nanostructures will be given based on our point of view.展开更多
The objectives of the present research are synthesizing three-dimensional （3D） nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nic...The objectives of the present research are synthesizing three-dimensional （3D） nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nickel nanostructures via reducing of nickel chloride with hydrazine hydrate in ethylene glycol solution at 100 ℃. The resulting Ni nanostructures were characterized by means of powder X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and selected-area electron diffraction （SAED）. And the magnetic properties of the 3D Ni nanostructures were measured as well. Results indicated that solvothermal process could be successfully used to prepare 3D dandelion-like nanostructures of Ni at a relatively mild temperature of 100℃. And the conclusions were made as follows： as-prepared Ni samples had obvious shape anisotropy and were composed of fine nanocrystallites, while they had significantly enhanced ferromagnetic properties than bulk Ni and Ni nanoparticles.展开更多
Gold nanoparticle arrays fabricated via layerby-layer technique were investigated using grazing-incidence small-angle X-ray scattering(GISAXS) method.Samples containing two gold nanoparticle layers that were separated...Gold nanoparticle arrays fabricated via layerby-layer technique were investigated using grazing-incidence small-angle X-ray scattering(GISAXS) method.Samples containing two gold nanoparticle layers that were separated by 5,11,15 and 21 poly electrolyte(PE) interlayers were studied.By using different X-ray incident angles,correlations of gold nanoparticles(GNPs) in the same layer and in two different layers were investigated.It is found that both sideway correlations between GNPs in the same layer and vertical correlation between two gold nanoparticle layers depend on the thickness of PE interlayers.According to sideway correlation,the size of GNPs is determined to be(13.0±0.5) nm in all of the four samples,which was also proved by scanning electron microscopy(SEM) and theoretical calculation of form factor of spherical particles.From vertical correlation,distance between two gold nanoparticle layers was determined for sample with 11,15 and 21 PE layers.These distances can be reasonably explained with the number of PE layers and the thickness of single PE layer.These results indicate that by repeated depositing of oppositely charged PE layers,a true three-dimensional(3 D) nanostructure can eventually be designed.展开更多
This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crus...This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance, low environmental impact, low cost, high gravimetric(2600 W h kg-1) and volumetric(2800 W h L-1) energy densities, assuming complete conversion of sulfur to lithium sulfide(Li2S)upon lithiation. However, lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides(Li2Sn, n=3–8), low electrical conductivity, and low loading density of sulfur. These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur. To overcome these issues, strategies have been pursued using nanotechnology applied to porous carbon nanocomposites, hollow one-dimensional carbon nanomaterials, graphene nanocomposites, and three-dimensional carbon nanostructured matrices. This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium–sulfur batteries. Furthermore, we highlight perspective research directions for commercialization of lithium–sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.展开更多
Abstract The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density w...Abstract The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density were collected outside of the reactor. The structure of the collected particles has been investigated by field scanning electron microscope （FESEM）, X-ray diffraction （XRD）, high resolution transmission electron microscopy （HRTEM） and selected area electron diffraction （SAED）. The analysis shows that uniform crystalline nuclei with average size of several nanometers have been formed in the scale of micro second through this reactive atmo- spheric plasma gas process. The crystallinity of the nanoparticles increases with power density. The high density of crystalline nanonuclei in the plasma gas phase and the low gas temperature are beneficial to the fast deposition of the 3D porous anatase TiO2 film.展开更多
A desirable methanol oxidation electrocatalyst was fabricated by metal atom diffusion to form an alloy of an assembled three-dimensional （3D） radial nanostructure of SnNi nanoneedles loaded with SnNiPt nanoparticles...A desirable methanol oxidation electrocatalyst was fabricated by metal atom diffusion to form an alloy of an assembled three-dimensional （3D） radial nanostructure of SnNi nanoneedles loaded with SnNiPt nanoparticles （NPs）.Herein,metal atom diffusion occurred between the SnNi support and loaded Pt NPs to form a SnNiPt ternary alloy on the catalyst surface.The as-obtained catalyst combines the excellent catalytic performance of the alloy and advantages of the 3D nanostructure;the SnNiPt NPs,which fused on the surface of the SnNi nanoneedle support,can dramatically improve the availability of Pt during electrocatalysis,and thus elevate the catalytic activity.In addition,the efficient mass transfer of the 3D nanostructure reduced the onset potential.Furthermore,the catalyst achieved a favorable CO poisoning resistance and enhanced stability.After atomic interdiffusion,the catalytic activity drastically increased by 45%,and the other performances substantially improved.These results demonstrate the significant advantage and enormous potential of the atomic interdiffusion treatment in catalytic applications.展开更多
CeO2 is an important porous material with a wide range of applications in the abatement of volatile organic compounds （VOCs）. In this paper, we prepared a series of novel three-dimensional （3D） micro/nanostructure...CeO2 is an important porous material with a wide range of applications in the abatement of volatile organic compounds （VOCs）. In this paper, we prepared a series of novel three-dimensional （3D） micro/nanostructured CeO2 materials via a solvothermal method. Organic acid-assisted synthesis and inorganic acid post-treatment were used to adjust the Ce02 microstructures. The size of the 3D micro/nanostructures could be controlled in the range from 180nm to 1.5 μm and the surface morphology changed from rough to smooth with the use of different organic acids. The CeO2 synthesized with acetic acid featured a hierarchical porosity and showed good performance for toluene catalytic combustion： a T50 of 187 ℃ and a T90 of 195 ℃. Moreover, the crystallite size, textural properties, and surface chemical states could be tuned by inorganic acid modification. After treatment with HNO3, the modified CeO2 materials exhibited improved catalytic activity, with a T50 of-175 ℃ and a T90 of -187 ℃. We concluded that the toluene combustion activity is related to the porosity and the amount of surface active oxygen of the CeO2. Both these features can be tuned by the co-work of organic and inorganic acids.展开更多
The commercialization of rechargeable Li metal batteries is hindered by dendrite growth and volumetric variation. Herein, we report a Li-rich dual-phase Li-Cu alloy with built-in 3 D conductive skeleton to replace con...The commercialization of rechargeable Li metal batteries is hindered by dendrite growth and volumetric variation. Herein, we report a Li-rich dual-phase Li-Cu alloy with built-in 3 D conductive skeleton to replace conventional planar Li anode. The Li-Cu alloy is simply prepared by fusion of Li and Cu metals at a relatively low-temperature of 500 °C, followed by a cooling process where phase-segregation leads to metallic Li phase distributed in the network of LiCu_x solid solution phase. Different from the common Li alloy, the electrochemical alloying reaction between Li and Cu metals is not observed. Therefore, the lithiophilic LiCu_x nanowires guides conformal plating of Li and the porous framework provides superior dimensional stability for the anode. This unique ferroconcrete-like structure of Li-Cu alloy enables dendrite-free Li plating for an expanded cycling lifetime. Constructing a new type of Li alloy with in situ formed electrochemically inactive framework is a promising and easily scaled-up strategy toward practical application of Li metal anodes.展开更多
State-of-the-art commercially available 3D laser micro-and nanoprinters using polymeric photoresists based on two-or multi-photon absorption rely on high-power pico-or femtosecond lasers,leading to fairly large and ex...State-of-the-art commercially available 3D laser micro-and nanoprinters using polymeric photoresists based on two-or multi-photon absorption rely on high-power pico-or femtosecond lasers,leading to fairly large and expensive instruments.Lately,we have introduced photoresists based on two-step absorption instead of two-photon absorption,allowing for the use of small and inexpensive continuous-wave 405 nm wavelength GaN semiconductor laser diodes with light-output powers below 1 mW.Here,using the identical photoresist system and similar laser diodes,we report on the design,construction,and characterization of a 3D laser nanoprinter that fits into a shoe box.This shoe box contains all optical components,namely the mounted laser,the collimation-and beam-shaping optics,a miniature MEMS xy-scanner,a tube lens,the focusing microscope objective lens(NA=1.4,100×magnification),a piezo slip-stick z-stage,the sample holder,a camera monitoring system,LED sample illumination,as well as the miniaturized control electronics employing a microcontroller.We present a gallery of example 3D structures printed with this instrument.We achieve about 100 nm lateral spatial resolution and focus scan speeds of about 1 mm/s.Potentially,our shoe-box-sized system can be made orders of magnitude less expensive than today’s commercial systems.展开更多
Ni-based electrocatalysts with strong redox abilities are active for the electrochemical oxidation of 5-hydroxymethylfurfural(HMF). Interface engineering is an efficient way to modulate the electronic structure, tune ...Ni-based electrocatalysts with strong redox abilities are active for the electrochemical oxidation of 5-hydroxymethylfurfural(HMF). Interface engineering is an efficient way to modulate the electronic structure, tune the intermediate adsorption, and expose more active sites. Herein, we increased the concentration of interfacial sites with rich defects in a 3D hierarchical nanostructured NiO-Co3O4 electrocatalyst and investigated its catalytic performance for HMF electro-oxidation. The interface effect created abundant cation vacancies, modulated the electronic properties of Co and Ni atoms, and raised the oxidation state of Ni species. The NiO-Co3O4 catalysts show superb HMF oxidation activities with a low onset potential of 1.28 VRHE.Meanwhile, in-situ surface-selective vibrational spectroscopy of sum-frequency generation was performed to study the reaction pathway during the oxidation process on the electrocatalysts. The current study offers an efficient way to create cation vacancies and proves the decisive role of cation vacancies in catalyzing the HMF electro-oxidation.展开更多
Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances ...Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.展开更多
Electrocatalytic carbon dioxide(CO_(2))reduction is considered as an economical and environmentally friendly approach to neutralizing and recycling greenhouse gas CO_(2).However,the design of preeminent and robust ele...Electrocatalytic carbon dioxide(CO_(2))reduction is considered as an economical and environmentally friendly approach to neutralizing and recycling greenhouse gas CO_(2).However,the design of preeminent and robust electrocatalysts for CO_(2)electroreduction is still challenging.Herein,we report the in-situ growth of dense CuO_(x)nanowire forest on 3D porous Cu foam(CuO_(x)-NWF@Cu-F),which can be directly applied as a freestanding and binder-free working electrode for highly effective electrocatalytic CO_(2)reduction.By adjusting the surface morphology and chemical composition of CuO_(x)nanowires via surface reconstruction,large electrochemically active surface area and abundant Cu(+1)sites were generated,leading to remarkable activity for CO_(2)electroreduction.The as-prepared hierarchical conductive electrode exhibited an enhanced Faradaic efficiency of 15.0%for ethanol formation(FE_(C_(2)H_(5)OH))and a total Faradaic efficiency of 69.4%for all carbonaceous compounds(FE_(C-total))at a mild applied potential of–0.45 V vs.RHE in 0.1 M KHCO_(3)electrolyte.It achieved a 4-fold increase in FE_(C-total)than that of Cu nanowire forest supported on 3D porous Cu foam(Cu-NWF@Cu-F)obtained by in-situ reduction of the CuO_(x)-NWF@Cu-F via annealing at H_(2)atmosphere,and thereby effectively suppressed the hydrogen evolution side-reaction.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))nanosheets have attracted widespread interest in the construction of advanced separation membranes.However,dense stacking and a single functionality have limited the membrane deve...Graphitic carbon nitride(g-C_(3)N_(4))nanosheets have attracted widespread interest in the construction of advanced separation membranes.However,dense stacking and a single functionality have limited the membrane development.Here,an advanced two-/three-dimensional(2D/3D)g-C_(3)N_(4)/TiO_(2)@MnO_(2) membrane is constructed by intercalating 3D TiO_(2)@MnO_(2) nanostructures into g-C_(3)N_(4) nanosheets.The 3D flower-like nanostructures broaden the transport channels of the composite membrane.The membrane can effectively separate five oil-in-water(O/W)emulsions,with a maximum flux of 3265.67±15.01 L·m^(-2)·h^(-1)·bar^(-1) and a maximum efficiency of 99.69%±0.45%for toluene-in-water emulsion(T/W).Meanwhile,the TiO_(2)@MnO_(2) acts as an excellent electron acceptor and provides positive spatial separation of electrons–holes(e^(-)–h^(+)).The formation of 2D/3D heterojunctions allows the material with wider light absorption and smaller bandgap(2.10 eV).These photoelectric properties give the membrane good degradation of three different pollutants,with about 100%degradation for methylene blue(MB)and malachite green(MG).The photocatalytic antibacterial efficiency of the membrane is also about 100%.After cyclic experiment,the membrane maintains its original separation and photocatalytic capabilities.The remarkable multifunctional and self-cleaning properties of the g-C_(3)N_(4) based membrane represent its potential value for complex wastewater treatment.展开更多
We report a three-dimensional hierarchical ternary hybrid composite of molybdenum disulfide(MoS2),reduced graphene oxide(GO),and carbon nano-tubes(CNTs)prepared by a two-step process.Firstly,reduced GO-CNT composites ...We report a three-dimensional hierarchical ternary hybrid composite of molybdenum disulfide(MoS2),reduced graphene oxide(GO),and carbon nano-tubes(CNTs)prepared by a two-step process.Firstly,reduced GO-CNT composites with three-dimensional microstructuresare synthesized by hydrothermal treatment of an aqueous dispersion of GO and CNTs to form a composite structure viaπ-πinteractions.Then,MoS2 nanoparticles are hydrothermally grown on the surfaces of the GO-CNT composite.This ternary composite shows superior electrocatalytic activity and stability in the hydrogen evolution reaction,with a low onset potential of only 35 mV,a Tafel slope of-38 mV.decade-1 and an apparent exchange current density of 74.25 mA.cm-2.The superior hydrogen evolution activity stemmed from the synergistic effect of MoS2 with its electrocatalytically active edge-sites and excellent electrical coupling to the underlying graphene and CNT network.展开更多
A micrometer-sized nanostructured,magnetic,ball-like FexOy-CeO2 composite was synthesized through an ethylene-glycol mediated process.The synthesized samples were characterized by scanning electron microscopy combined...A micrometer-sized nanostructured,magnetic,ball-like FexOy-CeO2 composite was synthesized through an ethylene-glycol mediated process.The synthesized samples were characterized by scanning electron microscopy combined with energydisperse X-ray analysis,transmission electron microscopy and X-ray powder diffraction.In the synthesis system,polyethylene glycol(PEG)and urea were found to play significant roles in the formation of the micrometer-sized spherical architecture of the precursor.The details of morphology and particle size could be changed with the initial concentration of Fe(NO3)3-9H2O and Ce(NO3)3-6H2O as the reactants.The magnetic FexOy-CeO2 composite with a similar morphology was readily obtained by calcination from the precursor.The characterization of transmission electron microscopy showed the calcined ball-like architecture was a highly porous structure consisting of many nanoparticles.Because of the micrometer-sized nanostructure and the multi-components as well as the magnetism,the as-obtained FexOy-CeO2 composite showed better activity and potentially easy recovery for the harmless degradation of hexachlorobenzene(HCB).展开更多
基金The US AMRDEC grant No.W911NF-16-2-0069“Enhanced Absorption in Stopped-Light Photonic Nanostructures:Applications to Efficient Sensing”EU LASERLAB-EUROPE(grant agreement No.871124Horizon 2020 research and innovation programme)projects are acknowleged for the financial support.D.G.acknowledges the financial support from the European Social Fund(project No 09.3.3-LMT-K712-17-0016)under grant agreement with the Research Council of Lithuania(LMTLT).
文摘The current study is directed to the rapidly developing field of inorganic material 3D object production at nano-/micro scale.The fabrication method includes laser lithography of hybrid organic-inorganic materials with subsequent heat treatment leading to a variety of crystalline phases in 3D structures.In this work,it was examined a series of organometallic polymer precursors with different silicon(Si)and zirconium(Zr)molar ratios,ranging from 9:1 to 5:5,prepared via sol-gel method.All mixtures were examined for perspective to be used in 3D laser manufacturing by fabricating nano-and micro-feature sized structures.Their spatial downscaling and surface morphology were evaluated depending on chemical composition and crystallographic phase.The appearance of a crystalline phase was proven using single-crystal X-ray diffraction analysis,which revealed a lower crystallization temperature for microstructures compared to bulk materials.Fabricated 3D objects retained a complex geometry without any distortion after heat treatment up to 1400℃.Under the proper conditions,a wide variety of crystalline phases as well as zircon(ZrSiO_(4)-a highly stable material)can be observed.In addition,the highest new record of achieved resolution below 60 nm has been reached.The proposed preparation protocol can be used to manufacture micro/nano-devices with high precision and resistance to high temperature and aggressive environment.
基金supported by the National Natural Science Foundation of China(21825501 and 21808124)China Postdoctoral Science Foundation(2017M620049 and 2019T120098)。
文摘Oxygen reduction reaction(ORR)is of significance for energy conversion technologies such as fuel cells and metal-air batteries[1,2].Currently,the electrocatalysts still need to employ expensive precious metal platinum(Pt)as the main active component to overcome the sluggish kinetics of ORR[3,4].The exploration of low-cost.
基金supported by an NSF CAREER Award(CMMI-1454293)a Grant-In-Aid(GIA)program/a start-up fund at the University of Minnesota,Twin Cities+2 种基金Parts of this work were carried out in the Characterization Facility,University of Minnesota,a member of the NSF-funded Materials Research Facilities Network(www.mrfn.org)via the MRSEC programA portion of this work was also carried out in the Minnesota Nano Center which receives partial support from the NSF through the NNCI programthe 3M Science and Technology Fellowship
文摘Grain coalescence has been applied in many areas of nanofabrication technology, including modification of thinfilm properties, nanowelding, and self-assembly of nanostructures. However, very few systematic studies of selfassembly using the grain coalescence, especially for threedimensional(3D) nanostructures, exist at present. Here, we investigate the mechanism of plasma triggered grain coalescence to achieve the precise control of nanoscale phase and morphology of the grain coalescence induced by exothermic energy. Exothermic energy is generated through etching a silicon substrate via application of plasma. By tuning the plasma power and the flow rates of reactive gases, different etching rates and profiles can be achieved, resulting in various morphologies of grain coalescence. Balancing the isotropic/anisotropic substrate etching profile and the etching rate makes it possible to simultaneously release 2D nanostructures from the substrate and induce enough surface tension force,generated by grain coalescence, to form 3D nanostructures.Diverse morphologies of 3D nanostructures have been obtained by the grain coalescence, and a strategy to achieve self-assembly, resulting in desired 3D nanostructures, has been proposed and demonstrated.
基金the support from the National Natural Science Foundation of China (22002068, 51772162 and 52072197)the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions, China (2019KJC004)+7 种基金the Outstanding Youth Foundation of Shandong Province (ZR2019JQ14)Taishan Scholar Young Talent Program (tsqn201909114)the Major Scientific and Technological Innovation Project (2019JZZY020405)the Major Basic Research Program of Natural Science Foundation of Shandong Province (ZR2020ZD09)China Postdoctoral Science Foundation (2021M691700)the Natural Science Foundation of Shandong Province of China (ZR2019BB002, ZR2018BB031)Australian Research Future Fellowship (FT210100298)CSIRO Energy Centre, and the Victorian Government’s support through the provision of a grant from Veski-Study Melbourne Research Partnerships Project。
文摘The development of efficient electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) with excellent catalytic performance and stability plays key roles in the commercialization of water splitting to generate hydrogen energy. Herein, a 2 D-3 D nanostructure composed of metal hydroxides and Prussian blue analogus(PBA) was in-situ decorated onto the Ni Fe foam(Pt-Ni Fe PBA) through a facile and scalable corrosive-coordinate approach. The specifically designed morphology favored the provision of abundant active sites, optimized the reaction pathway, and accelerated mass transport during the electrocatalytic process. Consequently, the as-synthesized Pt-Ni Fe PBA reached 10 m A cm^(-2) with small overpotentials of 29 and210 m V in 1 mol L;KOH deionized water for HER and OER,respectively. Remarkably, Pt-Ni Fe PBA required an overpotential of 21 m V to drive 10 m A cm^(-2) in seawater containing1 mol L;KOH with prominent durability. Moreover, with the as-synthesized Pt-Ni Fe PBA as bifunctional electrocatalyst,the Pt-Ni Fe PBA||Pt-Ni Fe PBA electrolyzer needed 1.46 and1.48 V to drive 10 m A cm^(-2) in 1 mol L;KOH with deionized water and 1 mol L;KOH with seawater, respectively. Remarkably, sustainable energies were utilized to power the overall water splitting and stored as easily portable hydrogen energy.
文摘Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and energy applications.Recently,the construction of a step-scheme heterostructure system(hereafter called the S-scheme)has received widespread attention in the photocatalytic field due to its ability to achieve efficient photogenerated carrier separation and obtain strong photo-redox ability.Herein,a novel S-scheme heterojunction system consisting of 2D O-doped g-C_(3)N_(4)(OCN)nanosheets and 3D N-doped Nb_(2)O_(5)/C(N-NBO/C)nanoflowers is constructed via ultrasonication and vigorous agitation technique followed by heat treatment for the photocatalytic degradation of Rhodamine B(RhB).Detailed characterization and decomposition behaviour of RhB showed that the fabricated material shows excellent photocatalytic efficiency and stability towards RhB photodegradation under visible-light illumination.The enhanced performance could be attributed to the following factors:fast charge transfer,highly-efficient charge separation,extended lifetime of photoinduced charge carriers,and the high redox capability of the photoinduced charges in the S-scheme system.Various trapping experiment conditions and electron paramagnetic resonance provide clear evidence of the S-scheme photogenerated charge transfer path,meanwhile,the RhB mineralization degradation pathway was also investigated using LC-MS.This study presents an approach to constructing Nb_(2)O_(5)-based S-scheme heterojunctions for photocatalytic applications.
基金financially supported by the National Natural Science Foundation of China(Nos.21504053 and 91527304)the Recruitment Program of Global Experts(No.15Z127060012)
文摘Structural DNA nanotechnology, an emerging technique that utilizes the nucleic acid molecule as generic polymer to programmably assemble well-defined and nano-sized architectures, holds great promise for new material synthesis and constructing functional nanodevices for different purposes. In the past three decades, rapid development of this technique has enabled the syntheses of hundreds and thousands of DNA nanostructures with various morphologies at different scales and dimensions. Among them, discrete three-dimensional （3D） DNA nanostructures not only represent the most advances in new material design, but also can serve as an excellent platform for many important applications. With precise spatial addressability and capability of arbitrary control over size, shape, and function, these nanostructures have drawn particular interests to scientists in different research fields. In this review article, we will briefly summarize the development regarding the synthesis of discrete DNA 3D nanostructures with various size, shape, geometry, and topology, including our previous work and recent progress by other groups. In detail, three methods majorly used to synthesize the DNA 3D objects will be introduced accordingly. Additionally, the principle, design rule, as well as pros and cons of each method will be highlighted. As functions of these discrete 3D nanostructures have drawn great interests to researchers, we will further discuss their cutting-edge applications in different areas, ranging from novel material synthesis, new device fabrication, and biomedical applications, etc. Lastly, challenges and outlook of these promising nanostructures will be given based on our point of view.
基金the Ministry of Science and Technology of China(No.2007CB607606,in the name of"973"Plan)is acknowledged.
文摘The objectives of the present research are synthesizing three-dimensional （3D） nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nickel nanostructures via reducing of nickel chloride with hydrazine hydrate in ethylene glycol solution at 100 ℃. The resulting Ni nanostructures were characterized by means of powder X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and selected-area electron diffraction （SAED）. And the magnetic properties of the 3D Ni nanostructures were measured as well. Results indicated that solvothermal process could be successfully used to prepare 3D dandelion-like nanostructures of Ni at a relatively mild temperature of 100℃. And the conclusions were made as follows： as-prepared Ni samples had obvious shape anisotropy and were composed of fine nanocrystallites, while they had significantly enhanced ferromagnetic properties than bulk Ni and Ni nanoparticles.
基金financially supported by the Framework Programme 7 Project NANOGOLD (No.ERAS-989409)。
文摘Gold nanoparticle arrays fabricated via layerby-layer technique were investigated using grazing-incidence small-angle X-ray scattering(GISAXS) method.Samples containing two gold nanoparticle layers that were separated by 5,11,15 and 21 poly electrolyte(PE) interlayers were studied.By using different X-ray incident angles,correlations of gold nanoparticles(GNPs) in the same layer and in two different layers were investigated.It is found that both sideway correlations between GNPs in the same layer and vertical correlation between two gold nanoparticle layers depend on the thickness of PE interlayers.According to sideway correlation,the size of GNPs is determined to be(13.0±0.5) nm in all of the four samples,which was also proved by scanning electron microscopy(SEM) and theoretical calculation of form factor of spherical particles.From vertical correlation,distance between two gold nanoparticle layers was determined for sample with 11,15 and 21 PE layers.These distances can be reasonably explained with the number of PE layers and the thickness of single PE layer.These results indicate that by repeated depositing of oppositely charged PE layers,a true three-dimensional(3 D) nanostructure can eventually be designed.
文摘This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance, low environmental impact, low cost, high gravimetric(2600 W h kg-1) and volumetric(2800 W h L-1) energy densities, assuming complete conversion of sulfur to lithium sulfide(Li2S)upon lithiation. However, lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides(Li2Sn, n=3–8), low electrical conductivity, and low loading density of sulfur. These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur. To overcome these issues, strategies have been pursued using nanotechnology applied to porous carbon nanocomposites, hollow one-dimensional carbon nanomaterials, graphene nanocomposites, and three-dimensional carbon nanostructured matrices. This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium–sulfur batteries. Furthermore, we highlight perspective research directions for commercialization of lithium–sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.
基金supported by National Natural Science Foundation of China(Nos.1083500410775031 and 11375042)+1 种基金Shanghai Municipal Committee of Science and Technology of China(10XD1400100)Outstanding Young Investigator Award(No.11005017)
文摘Abstract The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density were collected outside of the reactor. The structure of the collected particles has been investigated by field scanning electron microscope （FESEM）, X-ray diffraction （XRD）, high resolution transmission electron microscopy （HRTEM） and selected area electron diffraction （SAED）. The analysis shows that uniform crystalline nuclei with average size of several nanometers have been formed in the scale of micro second through this reactive atmo- spheric plasma gas process. The crystallinity of the nanoparticles increases with power density. The high density of crystalline nanonuclei in the plasma gas phase and the low gas temperature are beneficial to the fast deposition of the 3D porous anatase TiO2 film.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 21771140, 21471114, 91122103 and 51271132）.
文摘A desirable methanol oxidation electrocatalyst was fabricated by metal atom diffusion to form an alloy of an assembled three-dimensional （3D） radial nanostructure of SnNi nanoneedles loaded with SnNiPt nanoparticles （NPs）.Herein,metal atom diffusion occurred between the SnNi support and loaded Pt NPs to form a SnNiPt ternary alloy on the catalyst surface.The as-obtained catalyst combines the excellent catalytic performance of the alloy and advantages of the 3D nanostructure;the SnNiPt NPs,which fused on the surface of the SnNi nanoneedle support,can dramatically improve the availability of Pt during electrocatalysis,and thus elevate the catalytic activity.In addition,the efficient mass transfer of the 3D nanostructure reduced the onset potential.Furthermore,the catalyst achieved a favorable CO poisoning resistance and enhanced stability.After atomic interdiffusion,the catalytic activity drastically increased by 45%,and the other performances substantially improved.These results demonstrate the significant advantage and enormous potential of the atomic interdiffusion treatment in catalytic applications.
基金This work was financially supported by the Natural Science Foundation of China （21576054）, the Scientific Project of Guangdong Province （2014A010106030, 2016A010104017,2016B020241003）, and the Foundation of Higher Education of Guangdong Province （201 SICFSCX027） of China.
文摘CeO2 is an important porous material with a wide range of applications in the abatement of volatile organic compounds （VOCs）. In this paper, we prepared a series of novel three-dimensional （3D） micro/nanostructured CeO2 materials via a solvothermal method. Organic acid-assisted synthesis and inorganic acid post-treatment were used to adjust the Ce02 microstructures. The size of the 3D micro/nanostructures could be controlled in the range from 180nm to 1.5 μm and the surface morphology changed from rough to smooth with the use of different organic acids. The CeO2 synthesized with acetic acid featured a hierarchical porosity and showed good performance for toluene catalytic combustion： a T50 of 187 ℃ and a T90 of 195 ℃. Moreover, the crystallite size, textural properties, and surface chemical states could be tuned by inorganic acid modification. After treatment with HNO3, the modified CeO2 materials exhibited improved catalytic activity, with a T50 of-175 ℃ and a T90 of -187 ℃. We concluded that the toluene combustion activity is related to the porosity and the amount of surface active oxygen of the CeO2. Both these features can be tuned by the co-work of organic and inorganic acids.
基金the National Natural Science Foundation of China (21673033 and 21473022)the Science and Technology Department of Sichuan Province of China (2019YFH0001)the Fundamental Research Funds for the Central Universities (ZYGX2019J024)。
文摘The commercialization of rechargeable Li metal batteries is hindered by dendrite growth and volumetric variation. Herein, we report a Li-rich dual-phase Li-Cu alloy with built-in 3 D conductive skeleton to replace conventional planar Li anode. The Li-Cu alloy is simply prepared by fusion of Li and Cu metals at a relatively low-temperature of 500 °C, followed by a cooling process where phase-segregation leads to metallic Li phase distributed in the network of LiCu_x solid solution phase. Different from the common Li alloy, the electrochemical alloying reaction between Li and Cu metals is not observed. Therefore, the lithiophilic LiCu_x nanowires guides conformal plating of Li and the porous framework provides superior dimensional stability for the anode. This unique ferroconcrete-like structure of Li-Cu alloy enables dendrite-free Li plating for an expanded cycling lifetime. Constructing a new type of Li alloy with in situ formed electrochemically inactive framework is a promising and easily scaled-up strategy toward practical application of Li metal anodes.
基金We thank Vincent Hahn,Michael Thiel(Nanoscribe),and Matthias Blaicher(Nanoscribe)for discussions.We acknowledge funding by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy for the Excellence Cluster“3D Matter Made to Order”(2082/1-390761711)by the Carl Zeiss Foundation,by the Helmholtz program“Science and Technology of Nanosystems”,by the Karlsruhe School of Optics and Photonics(KSOP),by the Max Planck School of Photonics(MPSP)by Nanoscribe-A BICO company.
文摘State-of-the-art commercially available 3D laser micro-and nanoprinters using polymeric photoresists based on two-or multi-photon absorption rely on high-power pico-or femtosecond lasers,leading to fairly large and expensive instruments.Lately,we have introduced photoresists based on two-step absorption instead of two-photon absorption,allowing for the use of small and inexpensive continuous-wave 405 nm wavelength GaN semiconductor laser diodes with light-output powers below 1 mW.Here,using the identical photoresist system and similar laser diodes,we report on the design,construction,and characterization of a 3D laser nanoprinter that fits into a shoe box.This shoe box contains all optical components,namely the mounted laser,the collimation-and beam-shaping optics,a miniature MEMS xy-scanner,a tube lens,the focusing microscope objective lens(NA=1.4,100×magnification),a piezo slip-stick z-stage,the sample holder,a camera monitoring system,LED sample illumination,as well as the miniaturized control electronics employing a microcontroller.We present a gallery of example 3D structures printed with this instrument.We achieve about 100 nm lateral spatial resolution and focus scan speeds of about 1 mm/s.Potentially,our shoe-box-sized system can be made orders of magnitude less expensive than today’s commercial systems.
基金supported by the Fundamental Research Funds for the Central Universities (531118010127)the National Natural Science Foundation of China (21902047, 51402100, 21825201, 21573066, 21805080, 21972164, U19A2017)the Provincial Natural Science Foundation of Hunan (2016TP1009)。
文摘Ni-based electrocatalysts with strong redox abilities are active for the electrochemical oxidation of 5-hydroxymethylfurfural(HMF). Interface engineering is an efficient way to modulate the electronic structure, tune the intermediate adsorption, and expose more active sites. Herein, we increased the concentration of interfacial sites with rich defects in a 3D hierarchical nanostructured NiO-Co3O4 electrocatalyst and investigated its catalytic performance for HMF electro-oxidation. The interface effect created abundant cation vacancies, modulated the electronic properties of Co and Ni atoms, and raised the oxidation state of Ni species. The NiO-Co3O4 catalysts show superb HMF oxidation activities with a low onset potential of 1.28 VRHE.Meanwhile, in-situ surface-selective vibrational spectroscopy of sum-frequency generation was performed to study the reaction pathway during the oxidation process on the electrocatalysts. The current study offers an efficient way to create cation vacancies and proves the decisive role of cation vacancies in catalyzing the HMF electro-oxidation.
基金supported by Creative Materials Discovery Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(No.2020M3D1A1110522).
文摘Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.
基金grateful to the supports from the National Key R&D Program of China(No.2017YFA0208200)the National Natural Science Foundation of China(Nos.22022505,21872069)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.020514380266,020514380272,020514380274)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(No.BK20220008)the Nanjing International Collaboration Research Program(Nos.202201007,2022SX00000955)the Suzhou Gusu Leading Talent Program of Science and Technology Innovation and Entrepreneurship in Wujiang District(No.ZXL2021273).
文摘Electrocatalytic carbon dioxide(CO_(2))reduction is considered as an economical and environmentally friendly approach to neutralizing and recycling greenhouse gas CO_(2).However,the design of preeminent and robust electrocatalysts for CO_(2)electroreduction is still challenging.Herein,we report the in-situ growth of dense CuO_(x)nanowire forest on 3D porous Cu foam(CuO_(x)-NWF@Cu-F),which can be directly applied as a freestanding and binder-free working electrode for highly effective electrocatalytic CO_(2)reduction.By adjusting the surface morphology and chemical composition of CuO_(x)nanowires via surface reconstruction,large electrochemically active surface area and abundant Cu(+1)sites were generated,leading to remarkable activity for CO_(2)electroreduction.The as-prepared hierarchical conductive electrode exhibited an enhanced Faradaic efficiency of 15.0%for ethanol formation(FE_(C_(2)H_(5)OH))and a total Faradaic efficiency of 69.4%for all carbonaceous compounds(FE_(C-total))at a mild applied potential of–0.45 V vs.RHE in 0.1 M KHCO_(3)electrolyte.It achieved a 4-fold increase in FE_(C-total)than that of Cu nanowire forest supported on 3D porous Cu foam(Cu-NWF@Cu-F)obtained by in-situ reduction of the CuO_(x)-NWF@Cu-F via annealing at H_(2)atmosphere,and thereby effectively suppressed the hydrogen evolution side-reaction.
基金supported by the Fundamental Research Funds for the Central Universities,CHD(Nos.300102312403 and 300102313208)the Shaanxi Key Research&Development Project(No.2022GY-403)+1 种基金the Innovation Capability Support Program of Shaanxi(No.2023-CX-TD-43)the China Postdoctoral Science Foundation(No.2020M683395).
文摘Graphitic carbon nitride(g-C_(3)N_(4))nanosheets have attracted widespread interest in the construction of advanced separation membranes.However,dense stacking and a single functionality have limited the membrane development.Here,an advanced two-/three-dimensional(2D/3D)g-C_(3)N_(4)/TiO_(2)@MnO_(2) membrane is constructed by intercalating 3D TiO_(2)@MnO_(2) nanostructures into g-C_(3)N_(4) nanosheets.The 3D flower-like nanostructures broaden the transport channels of the composite membrane.The membrane can effectively separate five oil-in-water(O/W)emulsions,with a maximum flux of 3265.67±15.01 L·m^(-2)·h^(-1)·bar^(-1) and a maximum efficiency of 99.69%±0.45%for toluene-in-water emulsion(T/W).Meanwhile,the TiO_(2)@MnO_(2) acts as an excellent electron acceptor and provides positive spatial separation of electrons–holes(e^(-)–h^(+)).The formation of 2D/3D heterojunctions allows the material with wider light absorption and smaller bandgap(2.10 eV).These photoelectric properties give the membrane good degradation of three different pollutants,with about 100%degradation for methylene blue(MB)and malachite green(MG).The photocatalytic antibacterial efficiency of the membrane is also about 100%.After cyclic experiment,the membrane maintains its original separation and photocatalytic capabilities.The remarkable multifunctional and self-cleaning properties of the g-C_(3)N_(4) based membrane represent its potential value for complex wastewater treatment.
基金supported by the China Scholarship Council(CSC)the National Natural Science Foundation of China(Nos.11275203 and U1232128).
文摘We report a three-dimensional hierarchical ternary hybrid composite of molybdenum disulfide(MoS2),reduced graphene oxide(GO),and carbon nano-tubes(CNTs)prepared by a two-step process.Firstly,reduced GO-CNT composites with three-dimensional microstructuresare synthesized by hydrothermal treatment of an aqueous dispersion of GO and CNTs to form a composite structure viaπ-πinteractions.Then,MoS2 nanoparticles are hydrothermally grown on the surfaces of the GO-CNT composite.This ternary composite shows superior electrocatalytic activity and stability in the hydrogen evolution reaction,with a low onset potential of only 35 mV,a Tafel slope of-38 mV.decade-1 and an apparent exchange current density of 74.25 mA.cm-2.The superior hydrogen evolution activity stemmed from the synergistic effect of MoS2 with its electrocatalytically active edge-sites and excellent electrical coupling to the underlying graphene and CNT network.
基金the support from the Chinese Academy of Sciences(KZCX2-YW-420&KZCX2-YW-QN407)the National Basic Research Program of China(2009CB421606)+1 种基金the National Natural Science Foundation of China(20921063&20807049)the Project sponsored by Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education
文摘A micrometer-sized nanostructured,magnetic,ball-like FexOy-CeO2 composite was synthesized through an ethylene-glycol mediated process.The synthesized samples were characterized by scanning electron microscopy combined with energydisperse X-ray analysis,transmission electron microscopy and X-ray powder diffraction.In the synthesis system,polyethylene glycol(PEG)and urea were found to play significant roles in the formation of the micrometer-sized spherical architecture of the precursor.The details of morphology and particle size could be changed with the initial concentration of Fe(NO3)3-9H2O and Ce(NO3)3-6H2O as the reactants.The magnetic FexOy-CeO2 composite with a similar morphology was readily obtained by calcination from the precursor.The characterization of transmission electron microscopy showed the calcined ball-like architecture was a highly porous structure consisting of many nanoparticles.Because of the micrometer-sized nanostructure and the multi-components as well as the magnetism,the as-obtained FexOy-CeO2 composite showed better activity and potentially easy recovery for the harmless degradation of hexachlorobenzene(HCB).
