Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2...Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2)H_(4)·H_(2)O remains a major challenge,hindered by dynamic constraints.To address this,we prepared NiPt nanoparticles deposited onto urchin-like TiO_(2)(u-TiO_(2))using the impregnation-reduction method,resulting in the NiPt/u-TiO_(2)catalyst.Remarkably,the Ni0.5Pt0.5/u-TiO_(2)catalyst demonstrated 100%H_(2)selectivity,ultrahigh catalytic activity and remarkable durability for N_(2)H_(4)·H_(2)O dehydrogenation,with a turnover frequency(TOF)of115.8 min^(-1),surpassing that of the corresponding NiPt/commercial TiO_(2)(c-TiO_(2)).Characterization and experimental findings suggest that the remarkable activity may originate from the unique urchin-like structure of the catalyst,along with the synergistic interaction between NiPt metals and the support.This research opens new avenues for designing nanomaterials with morphology advantages for hydrogen evolution reaction.展开更多
3D urchin-like Co3O4 have been successfully prepared by calcination of the urchin-like precursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co3O4 h...3D urchin-like Co3O4 have been successfully prepared by calcination of the urchin-like precursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co3O4 have been characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray powder diffraction. The as-synthesized Co3O4 products are of urchin-like structures with approximated 5-7 μm in diameter, and are composed of numerous nanoparticles chains with the particles diameter of about 15 nm. This kind of urchin-like Co3O4 exhibits superior energy storage properties with the high capacity of 1.369 Ah/g and its good cyclic stability shows great potential in the rechargeable Li-ion battery.展开更多
It is well recognized that interfacial effect and/or impedance matching play a great impact on microwave absorption.Herein,we proposed a facile strategy to take full advantage of interface engineering and impedance ma...It is well recognized that interfacial effect and/or impedance matching play a great impact on microwave absorption.Herein,we proposed a facile strategy to take full advantage of interface engineering and impedance matching for boosting microwave absorption performance(MAPs).Three-dimensional(3D)hierarchical urchin-like core@shell structured NiO/Ni@CNTs multicomponent nanocomposites(MCNCs)were elaborately constructed and produced in high efficiency through a facile continuous chemical bath deposition,thermal treatment,and catalytic chemical vapor decomposition process.By controlling the pyrolysis time,the NiO/Ni@CNTs urchin-like MCNCs with different lengths and aggregation degrees of CNTs could be selectively synthesized.The obtained results revealed that the enhanced CNT contents provided abundant interfaces and effectively aggrandized their interfacial effects,which resulted in improved polarization loss,conductivity loss,and comprehensive MAPs.Impressively,the interfaces and impedance matching in the designed NiO/Ni@CNTs urchin-like MCNCs could be optimized by regulating the pyrolysis temperature,which further improved the comprehensive MAPs.And the designed NiO/Ni@CNTs urchin-like MCNCs could simultaneously display strong absorption capabilities,broad absorption bandwidths,and thin matching thicknesses.Therefore,our findings not only provided a simple and universal approach to produce core@shell structured magnetic carbon-based urchin-like MCNCs but also presented an interface engineering and impedance matching strategy to develop the tunable,strong absorption,broadband,lightweight high-efficiency microwave absorbers.展开更多
Selective cleavage of robust C−C bonds to harvest value-added aromatic oxygenates is an intriguing but challenging task in lignin depolymerization.Photocatalysis is a promising technology with the advantages of mild r...Selective cleavage of robust C−C bonds to harvest value-added aromatic oxygenates is an intriguing but challenging task in lignin depolymerization.Photocatalysis is a promising technology with the advantages of mild reaction conditions and strong sustainability.Herein,we show a novel urchin-like Nb_(2)O_(5)hollow microsphere(U-Nb_(2)O_(5)HM),prepared by one-pot hydrothermal method,are highly active and selective for C_(α)−C_(β)bond cleavage of ligninβ-O-4 model compounds under mild conditions,achieving 94%substrate conversion and 96%C−C bond cleavage selectivity.Systematic experimental studies and density functional theory(DFT)calculations revealed that the superior performance of U-Nb_(2)O_(5)HMs arises from more exposed active sites,more efficient free charge separation and the active(001)facet,which facilitates the activation of Cβ−H bond of lignin models and generate key Cβradical intermediates by photogenerated holes,further inducing the C_(α)−C_(β)bond cleavage to produce aromatic oxygenates.This work could provide some suggestions for the fabrication of hierarchical photocatalysts in the lignin depolymerization system.展开更多
Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange w...Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.展开更多
Developing efficient electrocatalysts for hydrogen evolution reaction(HER) is of great importance in contemporary water electrolysis technology. Here, a novel hierarchically sea urchin-like electrocatalyst(Mo_(4)O_(11...Developing efficient electrocatalysts for hydrogen evolution reaction(HER) is of great importance in contemporary water electrolysis technology. Here, a novel hierarchically sea urchin-like electrocatalyst(Mo_(4)O_(11)-MoS_(2)-VO_(2)) is synthesized by hydrothermal deposition and post-annealing strategy. The optimized electrocatalyst behaves as a high active hydrogen evolution electrode in 0.5 mol/L H_(2)SO_(4). This electrode needs overpotential of only 43 m V to achieve 10 m A/cm^(2)with a Tafel slope of 37 m V/dec and maintains its catalytic activity for at least 36 h. Better than most previously reported non-noble metal electrocatalysts anchored on carbon cloth. It is worth mentioning that the hierarchical sea urchin-like structure promotes the redistribution of electrons and provides more catalytic active sites. This strategy shows a way for the construction of inexpensive non-noble metal electrocatalysts in the future.展开更多
Spinel MnCo_(2)O_(4) is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox couples.However,low conductivity,poor rate capac...Spinel MnCo_(2)O_(4) is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox couples.However,low conductivity,poor rate capacity and rapid capacity fading have seriously impaired its practical applications.To overcome the inferiorities,urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays have been fabricated directly within a porous copper current collector via a facile hydrothermal method followed by a chemical vapor deposition carbonization process.In a typical nanowire,the core is composed of interconnected MnCo_(2)O_(4)nanoparticles and the shell shows as a thin amorphous carbon layer.The integrated MnCo_(2)O_(4)@C/Cu structure could act as working anodes without using additives or polymer binders.While MnCo_(2)O_(4)@C/Cu possesses slightly longer Li-ion insertion/desertion pathway than that of MnCo_(2)O_(4)/Cu,the carbon shell could effectively prevent the pulverization of MnCo_(2)O_(4) and lower down charge transfer resistance and actively participate in Li-ion cycles.The rearrangement of carbon atoms during lithiation/delithiation cycling could inhibit the formation of passive solid electrolyte interphase films.As a result,the MnCo_(2)O_(4)@C/Cu electrode presents superior rate capacity(600 mAh·g^(−1) at 1 A·g^(−1)) and better stability(797 mAh·g^(−1) after 200 cycles at 100 mA·g^(−1)).The excellent reversible Li ion storage capacity,cycling stability and rate capacity endow MnCo_(2)O_(4)@C/Cu great potential as stable and high output integrated anode materials in Li-ion batteries.展开更多
Based on a facile glucose-guided hydrolyzing-heat-treating approach,urchin-likeα-Fe2O3 nanomaterials with controllable morphology and crystallinity were prepared via adjusting the heat-treating temperature,and their ...Based on a facile glucose-guided hydrolyzing-heat-treating approach,urchin-likeα-Fe2O3 nanomaterials with controllable morphology and crystallinity were prepared via adjusting the heat-treating temperature,and their electrochemical performances were investigated.The results showed that changing the heat-treating temperature can effectively control the structure and electrochemical property of the as-made products.The urchin-likeα-Fe2O3 nanomaterials obtained by heat-treating at 300°C,composed of a mass of the shuttle fibrous brunches,had higher initial discharge capacity(1475 mAhg-1)than those consisting of nanorods formed at 700°C.The above difference is ascribed to the urchin-like samples obtained at the relatively low heat-treating temperature,which,with low crystallinity,large SBET,and well-regulated porous,is helpful to the adsorption of electrolyte and the transport of lithium ion,resulting in the high activity and discharge-charge capacity.展开更多
Large specific surface area is critical for Li4Ti5O12 to achieve good rate capacity and cycling stability, since it can increase the contact area between electrolyte/ electrode and shorten the transport paths for elec...Large specific surface area is critical for Li4Ti5O12 to achieve good rate capacity and cycling stability, since it can increase the contact area between electrolyte/ electrode and shorten the transport paths for electrons and lithium ions. In this study, hierarchical hollow Li4Ti5O12 urchin-like microspheres with ultra-high specific surface area of over 140 m2·g^-1 and diameter more than 500 nm have been successfully synthesized by combining the versatile sol-gel process and a hydrothermal reaction, and exhibit excellent electrochemical performance with a high specific capacity of 120 mA-h.g-1 at 20 C and long cycling stability of 〈 2% decay after 100 cycles. Ex situ electron energy loss spectroscopy （EELS） analysis of Li4Ti5O12 microspheres at different charge-discharge stages indicates that only a fraction of the TP＊ ions are reduced to Ti3＋ and a phase transformation occurs whereby the spinel phase Li4TisO12 is converted into the rock-salt phase Li7Ti5O12. Even after 100 cycles, the oxidation-reduction reaction between Ti3＋ and Ti4＋ can be carried out much more effectively on the surface of Li4Ti5O12 nanosheets than on commercially available Li4Ti5O12 particles. All the results suggest that these Li4Ti5O12 microspheres may be attractive candidate anode materials for lithium ion batteries.展开更多
Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced ...Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell per- formance even at half the thickness of a typical nanocrystalline TiO2 photoanode. In addition, this photoanode only required attaching -55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO2 coated urchin-like SnO2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO2 coated on urchin- like SnO2. TiO2 coated urchin-like SnO2 showed the highest value （76.1 ms） of electron lifetime （＇r） compared to 2.4 ms for bare urchin-like SnO2 and 14.9 ms for nanocrystalline TiO2. TiO2 coated SnO2 showed greatly enhanced open circuit voltage （Voc）, short-circuit current density （Jsc） and fill factor （FF） leading to a four-fold increase in efficiency increase compared to bare SnO2. Although TiO2 coated urchin-like SnO2 showed slightly lower cell efficiency than nanocrystalline TiO2, it only used a half thickness of photoanode and saved -45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO2.展开更多
Rechargeable Li-O2 batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy densityclose to the gasoline. Herein, Ag modified urchin-like α-MnO2 (Ag-MnO2) material with ...Rechargeable Li-O2 batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy densityclose to the gasoline. Herein, Ag modified urchin-like α-MnO2 (Ag-MnO2) material with hierarchical porous structure is obtained bya facile one-step hydrothermal method. Ag-MnO2 possesses thick nanowires and presents hierarchical porous structure of mesoporesand macropores. The unique structure can expose more active sites, and provide continuous pathways for O2 and discharge productsas well. The doping of Ag leads to the change of electronic distribution in α-MnO2 (i.e., more oxygen vacancies), which playimportant roles in improving their intrinsic catalytic activity and conductivity. As a result, LOBs with Ag-MnO2 catalysts exhibit loweroverpotential, higher discharge specific capacity and much better cycle stability compared to pure a-MnO2. LOBs with Ag-MnO2catalysts exhibit a superior discharge specific capacity of 13,131 mA·h·g^-1 at a current density of 200 mA·h·g^-1, a good cycle stabilityof 500 cycles at the capacity of 500 mA·h·g^-1. When current density is increased to 400 mA·h·g^-1, LOBs still retain a long lifespan of170 cycles at a limited capacity of 1,000 mA·h·g^-1.展开更多
The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering （SERS） properties. Here, we present a simple fabrication route to hexagonally arranged arrays of...The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering （SERS） properties. Here, we present a simple fabrication route to hexagonally arranged arrays of surface-roughened urchin- like Ag hemispheres （Ag-HSs） decorated with Ag nanoparticles （Ag-NPs） for highly active and reproducible SERS substrates. The urchin-like Ag-HS arrays are achieved by sputtering Ag onto the top surface of a highly ordered porous anodic aluminum oxide （AAO） template to form ordered arrays of smooth Ag-HSs and then by electrodepositing Ag-NPs onto the surface of each Ag-HS. Owing to the ordered arrangement of the Ag-HSs and the improved surface roughness, the urchin-like hierarchical Ag-HS arrays can provide sufficient and uniform ＂hot spots＂ for reproducible and highly active SERS effects. Using the urchin-like Ag-HS arrays as SERS substrates, 10-7 M dibutyl phthalate （a member of plasticizers family） and 1.5 × 10-5 M PCB-77 （one congener of polychlorinated biphenyl, a notorious class of pollutants） are identified, showing promising potential for these substrates in the rapid recognition of organic pollutants.展开更多
Aqueous Zn-ion batteries(AZIBs)are one of the promising battery technologies for the green energy storage and electric vehicles.As one attractive cathode material for AZIBs,α-MnO2 materials exhibit superior electroch...Aqueous Zn-ion batteries(AZIBs)are one of the promising battery technologies for the green energy storage and electric vehicles.As one attractive cathode material for AZIBs,α-MnO2 materials exhibit superior electrochemical properties.However,their long-term reversibility is still in great suspense.Considering the decisive effect of the structure and morphology on theα-MnO2 materials,hierarchicalα-MnO2 materials would be promising to improve the cycle performance of AZIB.Here,we synthesized theα-MnO2 urchin-like microspheres(AUM)via a self-assembled method.The porous microspheres composed of one-dimensionalα-MnO2 nanofibers with high crystallinity,which improved the surface area and active sites for Zn2+intercalation.The AUM-based AZIB realized a high initial capacity of 308.0 mA hg-1,and the highest energy density was 396.7 W hkg-1.The kinetics investigation confirmed the high capacitive contribution and fast ion diffusion of the AUM.Ex-situ XRD measurement further verified the synergistic insertion/extraction of H+and Zn2+ions during the charge/discharge process.The superiority of the AUM guaranteed good electrochemical performance and reversible phase evolution,and this application would promote the follow-up research on the advanced AZIB.展开更多
Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Pol...Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Polyethylene glycol (PEG) 200 and thiourea were used as a shape-control age nt and sulfur source for in-s让u sulfuration, respectively. The urchin-like NiC02S4 was characterized by X-ray powder diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and electrochemical measurements. The resulting NiCo2S4 with ion diffusion-favored structure demonstrated remarkable electrochemical characteristics for supercapacitor with a high specific capacitance (1334F/g at 0.5 A/g) and superior rate capability (78.1% of the original capacity from 0.5 to 20 A/g) in 6M KOH aqueous solution. Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4 as a positive electrode and activated carb on (AC) as a n egative electrode. A NiCo2Sj/AC device exhibited a high energy density of 37.32 Wh/kg at a power density of 317.8 W/kg with capacity retention of 91.9% and up to 2000 charge/discharge cycles at 3 A/g. The results demonstrate that the sea-urchin-like NiCo2S4 has potential applications in supercapacitors.展开更多
Designing highly reliable and practical microwave absorbers is one of the most important research directions in the microwave absorbing field.Many absorbents suffer from concentration-sensitivity and environmental-sen...Designing highly reliable and practical microwave absorbers is one of the most important research directions in the microwave absorbing field.Many absorbents suffer from concentration-sensitivity and environmental-sensitivity dilemmas in practical applications.Here,sea urchin-like aggregates of MnO_(2)nanotubes were synthesized by a simple hydrothermal method,which exhibit an outstanding impedance matching characteristic.The composites based on sea urchin-like aggregates of MnO_(2)nanotubes show excellent microwave absorption performance in a wide concentration domain from 20 wt.%to 70 wt.%,corresponding to electrical conductivities from 1.86×10^(−7)to 1.85×10^(−5)S/m.Such a wide concentration range of absorbent for excellent microwave absorption is mainly attributed to the beneficial impedance matching properties of sea urchin-like aggregates of hollow nanotubes.A competitive absorption bandwidth of 3.36 GHz is achieved at 1 mm thickness,which can be broadened to 13.4 GHz by structural design.This work shows a new scheme for designing reliable and practical microwave absorbers benefit from the wide absorbent concentration domain.展开更多
Surface engineering and Cu valence regulation are essential factors in improving the C_(2)selectivity during the electrochemical reduction of CO_(2).Herein,we present a sea urchin-like CuO/Cu_(2)O catalyst derived fro...Surface engineering and Cu valence regulation are essential factors in improving the C_(2)selectivity during the electrochemical reduction of CO_(2).Herein,we present a sea urchin-like CuO/Cu_(2)O catalyst derived from rhombic dodecahedra Cu_(2)O through one-step oxidation/etching method where the mixed Cu^(+)/Cu^(0)states are formed via in situ reduction during electrocatalysis.The combined effects of the morphology and the mixed Cu^(+)/Cu^(0)states on C–C coupling are evaluated by the Faradaic efficiency of C_(2)and the C_(2)/C1 ratio obtained in an H-cell.R-Cu^(O)/Cu_(2)O exhibited 49.5%Faradaic efficiency of C_(2)with a C_(2)/C1 ratio of 3.1 at−1.4 V vs.reversible hydrogen electrode,which are 1.5 and 3.2 times higher than those of R-Cu_(2)O,respectively.Using a flow-cell,68.0%Faradaic efficiency of C_(2)is achieved at a current density of 500 mA·cm^(−2).The formation of the mixed Cu^(+)/Cu^(0)states was confirmed by in situ Raman spectra.Additionally,the sea urchin-like structure provides more active sites and enables faster electron transfer.As a result,the excellent C_(2)production on R-CuO/Cu_(2)O is primarily attributed to the synergistic effects of the sea urchin-like structure and the stable mixed Cu^(+)/Cu^(0)states.Therefore,this work presents an integrated strategy for developing Cu-based electrocatalysts for C_(2)production through electrochemical CO_(2)reduction.展开更多
The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aeroge...The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aerogel matrix,modified with sea urchin-like magnetic Co/N-doped carbon@polyaniline(Co-NC@PANI),gelatin was introduced as the reinforcement phase of the aerogel backbone,and a microwave absorber with high efficiency and excellent performance was successfully prepared.The sea urchin-like Co-NC@PANI not only adjusted the impedance matching of the MXene but also introduced a magnetic loss mode into the composite.The multicomponent interfacial polarization,heterostructure,three-dimensional(3D)lightweight porous structure,and electromagnetic synergy strategy enabled the MXene-based aerogel modified by Co-NC@PANI(MCoP)to exhibit surprising EMW absorption properties.The maximum reflection loss(RL_(max))of the aerogel composite reached-62.4 dB,and the effective absorption bandwidth(EAB)reached 6.56 GHz when the loading was only 12%.In addition,through electromagnetic simulation experiments,the change in the electromagnetic field before and after EMW passed through the materials and the distribution of the volume loss density of EMW by the coaxial ring were observed.The coordinated electromagnetic balance strategy in the 3D network provides inspiration for the construction of materials and expands the research direction of lightweight and outstanding microwave absorbers.展开更多
In the present research,the fabrication and characterization of ZnS urchin-like nanoparticles(ULNPs)via simple,template free and onestep hydrothermal method are reported.Zinc acetate dihydrate,thiosemicarbazide and et...In the present research,the fabrication and characterization of ZnS urchin-like nanoparticles(ULNPs)via simple,template free and onestep hydrothermal method are reported.Zinc acetate dihydrate,thiosemicarbazide and ethylenediamine are utilized as precursors.Nanostructure characterization of three-dimension ZnS ULNPs is specified by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive x-ray spectroscopy(EDX),transmission electron microscopy(TEM),Fourier transforminfrared(FT-IR)andultraviolet-visible(UVVis)spectroscopy.The photocatalytic activity of ZnS NPs is determined bymeasuring the degradation of an organic dye methylene orange(MO)under UV-irradiation.The lattice characteristics such as nanocrystallite size,strain,stress,and deformation energy density are specified using Williamson-Hall(W-H)and Halder-Wagner(H-W)analysis with different considerations about the isotropic nature of the crystal.XRD analysis reveals that ZnS NPs are hexagonalwurtzite phase.The shape and mean diameter of NPs are demonstrated by TEM and SEM techniques to be 3D urchin-likewith an average size of 60 nm.N2 adsorption-desorption and UV-Vis spectroscopies are utilized to specify the optical characteristics such asmean pore diameter,total pore size,and BET special surface area.The band gap of fabrication ZnS NPs has been evaluated from the Tauc equation and absorption edge to be 3.84 eV.展开更多
Hierarchical urchin-like gamma-Al2O3 hollow microspheres were prepared by a hydrothermal method followed by a calcination process using Al(NO3)(3)center dot 9H(2)O as aluminum source, NH3 center dot H2O as precipitati...Hierarchical urchin-like gamma-Al2O3 hollow microspheres were prepared by a hydrothermal method followed by a calcination process using Al(NO3)(3)center dot 9H(2)O as aluminum source, NH3 center dot H2O as precipitating agent, and P123 as structure-directing agent (SDA). The obtained samples were investigated using X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and N-2 adsorption/desorption. The influences of P123 concentration, acidic condition, and hydrothermal time on the morphology of product were discussed. P123 has a great influence on ruling the oriented attachment of nanowires and stabilizing the superstructure in the self-assembly process. The 3D urchin-like hollow microspheres have a surface area of 210.2 m(2)/g and the average pore size is 11.42 nm, which have widely potential application such as catalyst, adsorption, and separation.展开更多
Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cyc...Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cycling stability,and excellent rate capability were achieved for the material due to its specific yolk–shell urchin-like porous structure and coated carbon layers.The pores distributed on the yolk and shell,as well as the gap between the yolk and shell,provide numerous pathways for the penetration of electrolyte,and enhance the reversible specific capacity(the initial discharge specific capacity was as high as 1405.7 mA h g^(-1) at 0.1 C).Meanwhile,the stress and volume expansion could be greatly released and relieved through the pores,and long cycling stability was achieved(a high reversible specific capacity of 502.7 mA h g^(-1) was maintained after 1000 cycles at 5 C).The coated carbon layers greatly enhance the conductivity of the yolk–shell urchin-like porous Co_(3)O_(4)/NiO microspheres,accelerate the transmission of electrons,and improve their rate performance(a reversible specific capacity of 397.5 mA h g^(-1) was achieved when the current density was increased to 10 C).展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22478001,U22A20408 and 22108238)the Excellent Young Scholars Program of Natural Science Foundation Anhui Province(No.2408085Y005)+3 种基金the Excellent Youth Scholars Program of Higher Education Institutions of Anhui Province(No.2024AH030008)the Open Fund of Shanghai Jiao Tong University Shaoxing Research Institute(No.JDSX2023014)the State Key Laboratory of Clean Energy Utilization(No.ZJUCEU2024017)the Outstanding Scientific Research and Innovation Team Program of Higher Education Institutions of Anhui Province(No.2023AH010015)
文摘Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2)H_(4)·H_(2)O remains a major challenge,hindered by dynamic constraints.To address this,we prepared NiPt nanoparticles deposited onto urchin-like TiO_(2)(u-TiO_(2))using the impregnation-reduction method,resulting in the NiPt/u-TiO_(2)catalyst.Remarkably,the Ni0.5Pt0.5/u-TiO_(2)catalyst demonstrated 100%H_(2)selectivity,ultrahigh catalytic activity and remarkable durability for N_(2)H_(4)·H_(2)O dehydrogenation,with a turnover frequency(TOF)of115.8 min^(-1),surpassing that of the corresponding NiPt/commercial TiO_(2)(c-TiO_(2)).Characterization and experimental findings suggest that the remarkable activity may originate from the unique urchin-like structure of the catalyst,along with the synergistic interaction between NiPt metals and the support.This research opens new avenues for designing nanomaterials with morphology advantages for hydrogen evolution reaction.
基金This work was supported by the National Natural Science Foundation of China （No.11074254）, the Ministry of Science and Technology of China （No.2005CB623603）, the Hundred Talent Program of Chinese Academy of Sciences, and the President Foundation of Hefei Institute of Physical Sciences.
文摘3D urchin-like Co3O4 have been successfully prepared by calcination of the urchin-like precursors, which were synthesized through a facile hydrothermal route. The morphology and structure of the 3D urchin-like Co3O4 have been characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray powder diffraction. The as-synthesized Co3O4 products are of urchin-like structures with approximated 5-7 μm in diameter, and are composed of numerous nanoparticles chains with the particles diameter of about 15 nm. This kind of urchin-like Co3O4 exhibits superior energy storage properties with the high capacity of 1.369 Ah/g and its good cyclic stability shows great potential in the rechargeable Li-ion battery.
基金financially supported by the Doctorial Start-up Fund of Guizhou University(2011–05)Fok Ying Tung Education Foundation(171095)+1 种基金Talent Project of Guizhou Provincial Education Department(2022–094)National Natural Science Foundation of China(No.11964006).
文摘It is well recognized that interfacial effect and/or impedance matching play a great impact on microwave absorption.Herein,we proposed a facile strategy to take full advantage of interface engineering and impedance matching for boosting microwave absorption performance(MAPs).Three-dimensional(3D)hierarchical urchin-like core@shell structured NiO/Ni@CNTs multicomponent nanocomposites(MCNCs)were elaborately constructed and produced in high efficiency through a facile continuous chemical bath deposition,thermal treatment,and catalytic chemical vapor decomposition process.By controlling the pyrolysis time,the NiO/Ni@CNTs urchin-like MCNCs with different lengths and aggregation degrees of CNTs could be selectively synthesized.The obtained results revealed that the enhanced CNT contents provided abundant interfaces and effectively aggrandized their interfacial effects,which resulted in improved polarization loss,conductivity loss,and comprehensive MAPs.Impressively,the interfaces and impedance matching in the designed NiO/Ni@CNTs urchin-like MCNCs could be optimized by regulating the pyrolysis temperature,which further improved the comprehensive MAPs.And the designed NiO/Ni@CNTs urchin-like MCNCs could simultaneously display strong absorption capabilities,broad absorption bandwidths,and thin matching thicknesses.Therefore,our findings not only provided a simple and universal approach to produce core@shell structured magnetic carbon-based urchin-like MCNCs but also presented an interface engineering and impedance matching strategy to develop the tunable,strong absorption,broadband,lightweight high-efficiency microwave absorbers.
基金financially supported by the National Natural Science Foundation of China (No. 22008073)Shanghai Sailing Program (No. 20YF1410600)
文摘Selective cleavage of robust C−C bonds to harvest value-added aromatic oxygenates is an intriguing but challenging task in lignin depolymerization.Photocatalysis is a promising technology with the advantages of mild reaction conditions and strong sustainability.Herein,we show a novel urchin-like Nb_(2)O_(5)hollow microsphere(U-Nb_(2)O_(5)HM),prepared by one-pot hydrothermal method,are highly active and selective for C_(α)−C_(β)bond cleavage of ligninβ-O-4 model compounds under mild conditions,achieving 94%substrate conversion and 96%C−C bond cleavage selectivity.Systematic experimental studies and density functional theory(DFT)calculations revealed that the superior performance of U-Nb_(2)O_(5)HMs arises from more exposed active sites,more efficient free charge separation and the active(001)facet,which facilitates the activation of Cβ−H bond of lignin models and generate key Cβradical intermediates by photogenerated holes,further inducing the C_(α)−C_(β)bond cleavage to produce aromatic oxygenates.This work could provide some suggestions for the fabrication of hierarchical photocatalysts in the lignin depolymerization system.
文摘Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.
基金supported by the National Natural Science Foundation of China (No. 51802177)Independent Cultivation Program of Innovation Team of Ji nan City (No. 2019GXRC011)Introduction and Cultivation Plan of Young Innovative Talents in Colleges and Universities of Shandong Province,Shandong Provincial Natural Science Foundation (No. ZR^(2)020ME052)。
文摘Developing efficient electrocatalysts for hydrogen evolution reaction(HER) is of great importance in contemporary water electrolysis technology. Here, a novel hierarchically sea urchin-like electrocatalyst(Mo_(4)O_(11)-MoS_(2)-VO_(2)) is synthesized by hydrothermal deposition and post-annealing strategy. The optimized electrocatalyst behaves as a high active hydrogen evolution electrode in 0.5 mol/L H_(2)SO_(4). This electrode needs overpotential of only 43 m V to achieve 10 m A/cm^(2)with a Tafel slope of 37 m V/dec and maintains its catalytic activity for at least 36 h. Better than most previously reported non-noble metal electrocatalysts anchored on carbon cloth. It is worth mentioning that the hierarchical sea urchin-like structure promotes the redistribution of electrons and provides more catalytic active sites. This strategy shows a way for the construction of inexpensive non-noble metal electrocatalysts in the future.
基金This study was financially supported by the National Natural Science Foundation of China(No.52072106)the Science and Technology Major Project of Anhui Province(No.202003a05020007)+2 种基金111 Project“New Materials and Technology for Clean Energy”(No.B18018)Fundamental Research Funds for the Central Universities of China(Nos.JZ2019HGBZ0134 and PA2019GDZC0096)the Enterprise Entrusted Project(No.W2021JSKF0868).
文摘Spinel MnCo_(2)O_(4) is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox couples.However,low conductivity,poor rate capacity and rapid capacity fading have seriously impaired its practical applications.To overcome the inferiorities,urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays have been fabricated directly within a porous copper current collector via a facile hydrothermal method followed by a chemical vapor deposition carbonization process.In a typical nanowire,the core is composed of interconnected MnCo_(2)O_(4)nanoparticles and the shell shows as a thin amorphous carbon layer.The integrated MnCo_(2)O_(4)@C/Cu structure could act as working anodes without using additives or polymer binders.While MnCo_(2)O_(4)@C/Cu possesses slightly longer Li-ion insertion/desertion pathway than that of MnCo_(2)O_(4)/Cu,the carbon shell could effectively prevent the pulverization of MnCo_(2)O_(4) and lower down charge transfer resistance and actively participate in Li-ion cycles.The rearrangement of carbon atoms during lithiation/delithiation cycling could inhibit the formation of passive solid electrolyte interphase films.As a result,the MnCo_(2)O_(4)@C/Cu electrode presents superior rate capacity(600 mAh·g^(−1) at 1 A·g^(−1)) and better stability(797 mAh·g^(−1) after 200 cycles at 100 mA·g^(−1)).The excellent reversible Li ion storage capacity,cycling stability and rate capacity endow MnCo_(2)O_(4)@C/Cu great potential as stable and high output integrated anode materials in Li-ion batteries.
基金supported by the National High-Tech Research and Development Program of China("863"Project)(Grant No.2006AA03A209)the New Century Excellent Talents from the Ministry of Education(Grant No.NCET-05-0660)+2 种基金the Natural Scientific Foundation of Zhejiang Province(Grant Nos.Y4080417,Y4090636)the New Bud Talents Grant from Zhejiang Province,Doctoral Start-up Foundation from Zhejiang Normal University(Grant No.ZC304009094)the Open Lab Project from Zhejiang Normal University
文摘Based on a facile glucose-guided hydrolyzing-heat-treating approach,urchin-likeα-Fe2O3 nanomaterials with controllable morphology and crystallinity were prepared via adjusting the heat-treating temperature,and their electrochemical performances were investigated.The results showed that changing the heat-treating temperature can effectively control the structure and electrochemical property of the as-made products.The urchin-likeα-Fe2O3 nanomaterials obtained by heat-treating at 300°C,composed of a mass of the shuttle fibrous brunches,had higher initial discharge capacity(1475 mAhg-1)than those consisting of nanorods formed at 700°C.The above difference is ascribed to the urchin-like samples obtained at the relatively low heat-treating temperature,which,with low crystallinity,large SBET,and well-regulated porous,is helpful to the adsorption of electrolyte and the transport of lithium ion,resulting in the high activity and discharge-charge capacity.
文摘Large specific surface area is critical for Li4Ti5O12 to achieve good rate capacity and cycling stability, since it can increase the contact area between electrolyte/ electrode and shorten the transport paths for electrons and lithium ions. In this study, hierarchical hollow Li4Ti5O12 urchin-like microspheres with ultra-high specific surface area of over 140 m2·g^-1 and diameter more than 500 nm have been successfully synthesized by combining the versatile sol-gel process and a hydrothermal reaction, and exhibit excellent electrochemical performance with a high specific capacity of 120 mA-h.g-1 at 20 C and long cycling stability of 〈 2% decay after 100 cycles. Ex situ electron energy loss spectroscopy （EELS） analysis of Li4Ti5O12 microspheres at different charge-discharge stages indicates that only a fraction of the TP＊ ions are reduced to Ti3＋ and a phase transformation occurs whereby the spinel phase Li4TisO12 is converted into the rock-salt phase Li7Ti5O12. Even after 100 cycles, the oxidation-reduction reaction between Ti3＋ and Ti4＋ can be carried out much more effectively on the surface of Li4Ti5O12 nanosheets than on commercially available Li4Ti5O12 particles. All the results suggest that these Li4Ti5O12 microspheres may be attractive candidate anode materials for lithium ion batteries.
文摘Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell per- formance even at half the thickness of a typical nanocrystalline TiO2 photoanode. In addition, this photoanode only required attaching -55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO2 coated urchin-like SnO2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO2 coated on urchin- like SnO2. TiO2 coated urchin-like SnO2 showed the highest value （76.1 ms） of electron lifetime （＇r） compared to 2.4 ms for bare urchin-like SnO2 and 14.9 ms for nanocrystalline TiO2. TiO2 coated SnO2 showed greatly enhanced open circuit voltage （Voc）, short-circuit current density （Jsc） and fill factor （FF） leading to a four-fold increase in efficiency increase compared to bare SnO2. Although TiO2 coated urchin-like SnO2 showed slightly lower cell efficiency than nanocrystalline TiO2, it only used a half thickness of photoanode and saved -45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO2.
基金This work was financially supported by High-level Talents'Discipline Construction Fund of Shandong University(No.31370089963078)Shandong Provincial Science and Technology Major Project(Nos.2016GGX104001,2017CXGC1010,and 2018JMRH0211)+2 种基金the Fundamental Research Funds of Shandong University(Nos.2016JC005,2017JC042 and 2017JC010)the Natural Science Foundation of Shandong Province(No.ZR2017MEM002)School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(No.DD29100027).
文摘Rechargeable Li-O2 batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy densityclose to the gasoline. Herein, Ag modified urchin-like α-MnO2 (Ag-MnO2) material with hierarchical porous structure is obtained bya facile one-step hydrothermal method. Ag-MnO2 possesses thick nanowires and presents hierarchical porous structure of mesoporesand macropores. The unique structure can expose more active sites, and provide continuous pathways for O2 and discharge productsas well. The doping of Ag leads to the change of electronic distribution in α-MnO2 (i.e., more oxygen vacancies), which playimportant roles in improving their intrinsic catalytic activity and conductivity. As a result, LOBs with Ag-MnO2 catalysts exhibit loweroverpotential, higher discharge specific capacity and much better cycle stability compared to pure a-MnO2. LOBs with Ag-MnO2catalysts exhibit a superior discharge specific capacity of 13,131 mA·h·g^-1 at a current density of 200 mA·h·g^-1, a good cycle stabilityof 500 cycles at the capacity of 500 mA·h·g^-1. When current density is increased to 400 mA·h·g^-1, LOBs still retain a long lifespan of170 cycles at a limited capacity of 1,000 mA·h·g^-1.
基金This work was financially supported by the National Basic Research Program of China （No. 2013CB934304）, the CAS/SAFEA International Partnership Program for Creative Research Teams, the National NaturalScience Foundation of China （Nos. 21303211, 11274312 and 51472245）.
文摘The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering （SERS） properties. Here, we present a simple fabrication route to hexagonally arranged arrays of surface-roughened urchin- like Ag hemispheres （Ag-HSs） decorated with Ag nanoparticles （Ag-NPs） for highly active and reproducible SERS substrates. The urchin-like Ag-HS arrays are achieved by sputtering Ag onto the top surface of a highly ordered porous anodic aluminum oxide （AAO） template to form ordered arrays of smooth Ag-HSs and then by electrodepositing Ag-NPs onto the surface of each Ag-HS. Owing to the ordered arrangement of the Ag-HSs and the improved surface roughness, the urchin-like hierarchical Ag-HS arrays can provide sufficient and uniform ＂hot spots＂ for reproducible and highly active SERS effects. Using the urchin-like Ag-HS arrays as SERS substrates, 10-7 M dibutyl phthalate （a member of plasticizers family） and 1.5 × 10-5 M PCB-77 （one congener of polychlorinated biphenyl, a notorious class of pollutants） are identified, showing promising potential for these substrates in the rapid recognition of organic pollutants.
基金supported by the National Key Research and Development Program of China(2016YFA0202400)the 111 Project(B16016)+1 种基金the National Natural Science Foundation of China(51702096,U1705256 and 51572080)the Fundamental Research Funds for the Central Universities(2018ZD07 and JB2019132)。
文摘Aqueous Zn-ion batteries(AZIBs)are one of the promising battery technologies for the green energy storage and electric vehicles.As one attractive cathode material for AZIBs,α-MnO2 materials exhibit superior electrochemical properties.However,their long-term reversibility is still in great suspense.Considering the decisive effect of the structure and morphology on theα-MnO2 materials,hierarchicalα-MnO2 materials would be promising to improve the cycle performance of AZIB.Here,we synthesized theα-MnO2 urchin-like microspheres(AUM)via a self-assembled method.The porous microspheres composed of one-dimensionalα-MnO2 nanofibers with high crystallinity,which improved the surface area and active sites for Zn2+intercalation.The AUM-based AZIB realized a high initial capacity of 308.0 mA hg-1,and the highest energy density was 396.7 W hkg-1.The kinetics investigation confirmed the high capacitive contribution and fast ion diffusion of the AUM.Ex-situ XRD measurement further verified the synergistic insertion/extraction of H+and Zn2+ions during the charge/discharge process.The superiority of the AUM guaranteed good electrochemical performance and reversible phase evolution,and this application would promote the follow-up research on the advanced AZIB.
文摘Nickel cobalt sulfides (MCo2S4) have attracted considerable attention as electrode materials for supercapacitors. Herein, a sea-urchin-like NiCo2S4 material was synthesized through a one-step solvothermal process. Polyethylene glycol (PEG) 200 and thiourea were used as a shape-control age nt and sulfur source for in-s让u sulfuration, respectively. The urchin-like NiC02S4 was characterized by X-ray powder diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and electrochemical measurements. The resulting NiCo2S4 with ion diffusion-favored structure demonstrated remarkable electrochemical characteristics for supercapacitor with a high specific capacitance (1334F/g at 0.5 A/g) and superior rate capability (78.1% of the original capacity from 0.5 to 20 A/g) in 6M KOH aqueous solution. Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4 as a positive electrode and activated carb on (AC) as a n egative electrode. A NiCo2Sj/AC device exhibited a high energy density of 37.32 Wh/kg at a power density of 317.8 W/kg with capacity retention of 91.9% and up to 2000 charge/discharge cycles at 3 A/g. The results demonstrate that the sea-urchin-like NiCo2S4 has potential applications in supercapacitors.
基金the National Natural Science Foundation of China(Nos.62175010 and 62005010)Aeronautical Science Foundation of China(No.202000270S9002).
文摘Designing highly reliable and practical microwave absorbers is one of the most important research directions in the microwave absorbing field.Many absorbents suffer from concentration-sensitivity and environmental-sensitivity dilemmas in practical applications.Here,sea urchin-like aggregates of MnO_(2)nanotubes were synthesized by a simple hydrothermal method,which exhibit an outstanding impedance matching characteristic.The composites based on sea urchin-like aggregates of MnO_(2)nanotubes show excellent microwave absorption performance in a wide concentration domain from 20 wt.%to 70 wt.%,corresponding to electrical conductivities from 1.86×10^(−7)to 1.85×10^(−5)S/m.Such a wide concentration range of absorbent for excellent microwave absorption is mainly attributed to the beneficial impedance matching properties of sea urchin-like aggregates of hollow nanotubes.A competitive absorption bandwidth of 3.36 GHz is achieved at 1 mm thickness,which can be broadened to 13.4 GHz by structural design.This work shows a new scheme for designing reliable and practical microwave absorbers benefit from the wide absorbent concentration domain.
基金supported by the National Natural Science Foundation of China(Grant No.22178266).
文摘Surface engineering and Cu valence regulation are essential factors in improving the C_(2)selectivity during the electrochemical reduction of CO_(2).Herein,we present a sea urchin-like CuO/Cu_(2)O catalyst derived from rhombic dodecahedra Cu_(2)O through one-step oxidation/etching method where the mixed Cu^(+)/Cu^(0)states are formed via in situ reduction during electrocatalysis.The combined effects of the morphology and the mixed Cu^(+)/Cu^(0)states on C–C coupling are evaluated by the Faradaic efficiency of C_(2)and the C_(2)/C1 ratio obtained in an H-cell.R-Cu^(O)/Cu_(2)O exhibited 49.5%Faradaic efficiency of C_(2)with a C_(2)/C1 ratio of 3.1 at−1.4 V vs.reversible hydrogen electrode,which are 1.5 and 3.2 times higher than those of R-Cu_(2)O,respectively.Using a flow-cell,68.0%Faradaic efficiency of C_(2)is achieved at a current density of 500 mA·cm^(−2).The formation of the mixed Cu^(+)/Cu^(0)states was confirmed by in situ Raman spectra.Additionally,the sea urchin-like structure provides more active sites and enables faster electron transfer.As a result,the excellent C_(2)production on R-CuO/Cu_(2)O is primarily attributed to the synergistic effects of the sea urchin-like structure and the stable mixed Cu^(+)/Cu^(0)states.Therefore,this work presents an integrated strategy for developing Cu-based electrocatalysts for C_(2)production through electrochemical CO_(2)reduction.
文摘The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aerogel matrix,modified with sea urchin-like magnetic Co/N-doped carbon@polyaniline(Co-NC@PANI),gelatin was introduced as the reinforcement phase of the aerogel backbone,and a microwave absorber with high efficiency and excellent performance was successfully prepared.The sea urchin-like Co-NC@PANI not only adjusted the impedance matching of the MXene but also introduced a magnetic loss mode into the composite.The multicomponent interfacial polarization,heterostructure,three-dimensional(3D)lightweight porous structure,and electromagnetic synergy strategy enabled the MXene-based aerogel modified by Co-NC@PANI(MCoP)to exhibit surprising EMW absorption properties.The maximum reflection loss(RL_(max))of the aerogel composite reached-62.4 dB,and the effective absorption bandwidth(EAB)reached 6.56 GHz when the loading was only 12%.In addition,through electromagnetic simulation experiments,the change in the electromagnetic field before and after EMW passed through the materials and the distribution of the volume loss density of EMW by the coaxial ring were observed.The coordinated electromagnetic balance strategy in the 3D network provides inspiration for the construction of materials and expands the research direction of lightweight and outstanding microwave absorbers.
基金Islamic Azad University,Tonekabon Branch for financial support throughout this research project.
文摘In the present research,the fabrication and characterization of ZnS urchin-like nanoparticles(ULNPs)via simple,template free and onestep hydrothermal method are reported.Zinc acetate dihydrate,thiosemicarbazide and ethylenediamine are utilized as precursors.Nanostructure characterization of three-dimension ZnS ULNPs is specified by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive x-ray spectroscopy(EDX),transmission electron microscopy(TEM),Fourier transforminfrared(FT-IR)andultraviolet-visible(UVVis)spectroscopy.The photocatalytic activity of ZnS NPs is determined bymeasuring the degradation of an organic dye methylene orange(MO)under UV-irradiation.The lattice characteristics such as nanocrystallite size,strain,stress,and deformation energy density are specified using Williamson-Hall(W-H)and Halder-Wagner(H-W)analysis with different considerations about the isotropic nature of the crystal.XRD analysis reveals that ZnS NPs are hexagonalwurtzite phase.The shape and mean diameter of NPs are demonstrated by TEM and SEM techniques to be 3D urchin-likewith an average size of 60 nm.N2 adsorption-desorption and UV-Vis spectroscopies are utilized to specify the optical characteristics such asmean pore diameter,total pore size,and BET special surface area.The band gap of fabrication ZnS NPs has been evaluated from the Tauc equation and absorption edge to be 3.84 eV.
基金This work was financially supported by National Natural Science Foundation of China，State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology)
文摘Hierarchical urchin-like gamma-Al2O3 hollow microspheres were prepared by a hydrothermal method followed by a calcination process using Al(NO3)(3)center dot 9H(2)O as aluminum source, NH3 center dot H2O as precipitating agent, and P123 as structure-directing agent (SDA). The obtained samples were investigated using X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and N-2 adsorption/desorption. The influences of P123 concentration, acidic condition, and hydrothermal time on the morphology of product were discussed. P123 has a great influence on ruling the oriented attachment of nanowires and stabilizing the superstructure in the self-assembly process. The 3D urchin-like hollow microspheres have a surface area of 210.2 m(2)/g and the average pore size is 11.42 nm, which have widely potential application such as catalyst, adsorption, and separation.
基金supported by the National Natural Science Foundation of China(51725101,11727807,51672050,61790581)the Ministry of Science and Technology of China(973 Project No.2018YFA0209102)the science and technology research project of Jiangxi Provincial Department of Education(GJJ200338).
文摘Yolk–shell urchin-like porous Co_(3)O_(4)/NiO@C microspheres were successfully synthesized via a facile solvothermal method and annealing treatment under an argon atmosphere.High reversible specific capacity,long cycling stability,and excellent rate capability were achieved for the material due to its specific yolk–shell urchin-like porous structure and coated carbon layers.The pores distributed on the yolk and shell,as well as the gap between the yolk and shell,provide numerous pathways for the penetration of electrolyte,and enhance the reversible specific capacity(the initial discharge specific capacity was as high as 1405.7 mA h g^(-1) at 0.1 C).Meanwhile,the stress and volume expansion could be greatly released and relieved through the pores,and long cycling stability was achieved(a high reversible specific capacity of 502.7 mA h g^(-1) was maintained after 1000 cycles at 5 C).The coated carbon layers greatly enhance the conductivity of the yolk–shell urchin-like porous Co_(3)O_(4)/NiO microspheres,accelerate the transmission of electrons,and improve their rate performance(a reversible specific capacity of 397.5 mA h g^(-1) was achieved when the current density was increased to 10 C).
