Kinetics Study on Photocatalytic Degradation of Methyl Orange Catalyzed by Sea Urchin-Like Cu2O

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.

Synthetic strategy of biomimetic sea urchin-like Co-NC@PANI modified MXene-based magnetic aerogels with enhanced electromagnetic wave absorption properties

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.

Integration of urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays within porous copper current collector for superior performance Li-ion battery anodes

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.

Combined effects of sea urchin-like structure and mixed Cu^(+)/Cu^(0)states on promoting C_(2)formation in electrocatalytic CO_(2)reduction

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.

Nanoarchitectonics of MnO_(2)nanotubes as sea urchin-like aggregates for dielectric response and microwave absorption with a wide concentration domain

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.

Interfacial coupling of sea urchin-like(Mo4O11-MoS2-VO_(2)) promoted electron redistributions for significantly boosted hydrogen evolution reaction

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.

Hexagonally arranged arrays of urchin-like Ag hemispheres decorated with Ag nanoparticles for surface-enhanced Raman scattering substrates

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.

Ag doped urchin-like α-MnO2 toward efficient and bifunctional electrocatalysts for Li-02 batteries

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.

Urchin-like NiCo2S4 structures synthesized through a one-step solvothermal process for high-performance supercapacitors

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.

Preparation and electrochemical properties of urchin-like α-Fe_2O_3 nanomaterials

Based on a facile glucose-guided hydrolyzing-heat-treating approach, urchin-like α-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-like α-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.

Urchin-like Nb_(2)O_(5)hollow microspheres enabling efficient and selective photocatalytic C–C bond cleavage in lignin models under ambient conditions

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.

Photocatalytic activity,nanostructure and optical properties of 3D ZnS urchin-like via hydrothermal method

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.

Synthesis of urchin-like Sn–ZnO–C composite and its enhanced electrochemical performance for lithium-ion batteries

Urchin-like Sn–ZnO–C composite have been successfully prepared by thermal annealing of ZnSn(OH)6precursor in acetylene/argon gas(1/9;v/v).The phase of the urchin-like Sn–ZnO–C has been characterized by X-ray diffraction(XRD)and Raman spectrum.The images of scanning electron microscopy(SEM)and transmission electron microscope(TEM)demonstrate that the Sn–ZnO–C composite with an average of 3 lm in diameter is composed of many core–shell nanowires and carbon nanotubes emanated from the center.The thermal annealing temperature and time have crucial effects on the formation of urchin-like structure and carbon content of the Sn–ZnO–C composites.As an anode for lithium-ion batteries,the urchin-like Sn–ZnO–C composite delivers a discharge capacity of 1,034.5 mAh/g in initial cycle and 571.9 mAh/g reversible discharge capacity after 25 cycles at a current density of 50 mA/g.The superior energy storage properties highlight the urchin-like Sn–ZnO–C composite as a potential alternative anode material in lithium-ion batteries.

P123 assisted synthesis and characterization of urchin-like y-Al2O3 hollow microspheres

层次像顽童的 -Al2O3 空 microspheres 被一个锻烧过程用艾尔跟随的一个热水的方法准备(没有 3)3

Synchronous organic-inorganic co-intercalated ammonium vanadate cathode for advanced aqueous zinc-ion batteries

Vanadium-based cathode materials are attractive for aqueous zinc-ion batteries(AZIBs)owing to the high capacity from their open frameworks and multiple valences.However,the cycle stability and rate capability are still restricted by the low electrical conductivity and trapped diffusion kinetics.Here,we propose an organic-inorganic co-intercalation strategy to regulate the structure of ammonium vanadate(NH_(4)V_(4)O_(10),NVO).The introduction of Al^(3+)and polyaniline(PANI)induces the optimized layered structure and generation of urchin-like hierarchical construction(AP-NVO),based on heterogeneous nucleation and dissolution-recrystallization growth mechanism.Owing to these favorable features,the AP-NVO electrode delivers a desirable discharge capacity of 386 mA h g^(-1) at 1.0 A g^(-1),high-rate capability of 263 mA h g^(-1 )at 5.0 A g^(-1) and excellent cycling stability with 80.4%capacity retention over 2000 cycles at 5.0 A g^(-1).Such satisfactory electrochemical performance is believed to result from the enhanced reaction kinetics provided by the stable layered structure and a high intercalation pseudo-capacitance reaction.These results could provide enlightening insights into the design of layered vanadium oxide cathodematerials.

类海胆状TiO_(2)@C微球复合材料高性能钠离子电池负极材料的研究

本工作报道了一种简单且成本低廉的水热方法合成了由碳包覆的高结晶度TiO_(2)纳米棒构成的具有放射状类海胆结构的TiO_(2)@C微米球复合材料(SUL-TiO_(2)@C)钠离子电池负极材料。SUL-TiO_(2)@C表现出多孔的类海胆状结构,由径向生长的金红石纳米棒和包覆其纳米棒的无序碳涂层组成。通过扫描电子显微镜和透射电子显微镜、X射线衍射仪、全自动氮吸附比表面积分析仪、拉曼光谱仪、X射线光电子能谱仪、电化学工作站和电池测试系统对无碳包覆的TiO_(2)(记为SUL-TiO_(2))和SUL-TiO_(2)@C进行表面形貌、晶体结构、比表面积、碳结构、表面元素组成和价态、赝电容行为、循环性能与倍率性能等分析对比,研究结果表明:本项目制备的SUL-TiO_(2)@C复合材料具有更高比例的{110}面、更大的比表面积、更高比例的赝电容贡献、更大的放电比容量和优异的倍率性能。本工作的合成方法为钠离子电池负电极材料研究及未来的应用提供了参考价值和应用价值。

新型海胆状钨铜自支撑电极的制备及其葡萄糖无酶传感

该文采用方波脉冲法在光滑W_(7)0Cu_(30)电极表面快速、高效制备海胆状结构的自支撑电极(U-WCu),并用于葡萄糖的电化学检测,其表现出比单一纳米铜(N-Cu)更优异的电化学性能。考察了脉冲时间、脉冲频率和电势范围对葡萄糖电催化氧化的影响。采用循环伏安法(CV)比较了U-WCu电极和N-Cu电极在0.1 mol/L NaOH溶液中对葡萄糖的电催化氧化行为,构建了基于U-WCu海胆状电极的无酶电化学传感器。该电极的线性范围宽(2μmol/L~10 mmol/L),检出限(S/N=3)低至0.21μmol/L,灵敏度高达4983μA∙mmol∙L^(−1)∙cm^(−2)。方法有极好的重复性、重现性,良好的抗干扰性,以及长达8周的稳定性,并成功用于葡萄糖注射液中葡萄糖含量的测定。

高分子模板调控不同形貌氧化亚铜的仿生合成

采用聚丙烯酰胺(PAM)为软模板,在CuSO4、Na2SO3体系中调控合成了片状、海胆状、一维线、针状聚集体氧化亚铜晶体。研究了不同浓度Cu2+、不同PAM含量及不同温度对晶体生长的影响。结果表明,PAM促使氧化亚铜异相成核,氧化亚铜形貌随PAM质量分数的变化而变化:当c(Cu2+)=0.5mol.L-1时,PAM质量分数为3.0%(常温引入体系),产物主要为片状晶体;PAM质量分数为1.0%、3.0%时(高温引入体系),分别获得一维线状、海胆状晶体;当Cu2+浓度为0.1 mol.L-1时,体系中高温引入质量分数3.0%的PAM,得到片层状晶体;当Cu2+浓度为0.3、0.4 mol.L-1时,得到针状聚集体氧化亚铜晶体。分别用X射线粉末衍射、冷场发射扫描电子显微镜和激光粒度仪对所制备的产品进行了表征。