Sea Urchin-like Structure Research Articles

Efficient broadband sea urchin-like Fe3O4@C electromagnetic wave absorbing materials

The development of electromagnetic wave absorbing materials is crucial for various applications. Carbon materials and ferrite materials were recognized as ideal candidates of absorbing agents due to their respective dielectric loss and magnetic loss capabilities. In this study, Fe3O4@C were prepared using hydrothermal carbonization coupling method. The microstructure and morphology of Fe3O4@C were studied using SEM, TEM, XRD and TG. The results showed that Fe3O4@C exhibited a hollow sea urchin-like structure. The molar ratio of carbon to iron sources in the raw materials significantly influenced the crystal structure of the product. The growth mechanism of sea urchin-like Fe3O4@C was proposed. The carbon content in Fe3O4@C increased with the increase of molar ratio of glucose and iron (III) sulfate. The Fe3O4@C with carbon content of 31.10 % exhibited optimal absorption performance, with a minimum reflection loss of −57.1 dB at a matching thickness of 5.10 mm and effective absorption bandwidth (EAB) of 4 GHz. Electromagnetic parameters and absorption performance could be adjusted by varying the molar ratio of glucose and iron (III) sulfate. The unique sea urchin-like structure enhanced multiple reflection of electromagnetic waves. Interface polarization, conductivity loss and synergistic effect between carbon and Fe3O4 also contributed to the favorable absorption properties.

Enhanced photoelectrochemical water splitting by a 3D hierarchical sea urchin-like structure: ZnO nanorod arrays on TiO2 hollow hemisphere

A hierarchical sea urchin-like hybrid metal oxide nanostructure of ZnO nanorods deposited on TiO2 porous hollow hemispheres with a thin zinc titanate interface layer is specifically designed and synthesized to form a combined type I straddling and type II staggered junctions. The HHSs, synthesized by electrospinning, facilitate light trapping and scattering. The ZnO nanorods offer a large surface area for improved surface oxidation kinetics. The interface layer of zinc titanate (ZnTiO3) between the TiO2 HHSs and ZnO nanorods regulates the charge separation in a closely coupled hierarchy structure of ZnO/ZnTiO3/TiO2. The synergistic effects of the improved light trapping, charge separation, and fast surface reaction kinetics result in a superior photoconversion efficiency of 1.07% for the photoelectrochemical water splitting with an outstanding photocurrent density of 2.8 mA cm−2 at 1.23 V versus RHE.

Collaborative electrospinning and ice-templating for sea urchin-inspired aerogel microsphere: Unraveling functional mechanisms in thermally conductive phase change composites

With the increased integration of electronic devices, effective heat management becomes imperative. Thermally conductive phase change composites play a vital role by efficiently conducting heat and utilizing matrix phase change for heat storage. Conventional materials encounter difficulties such as low thermal conductivity, restricted heat storage density, and vulnerability to leakage. This study presents a novel method combining electrospinning and ice-templating method to produce aerogel microspheres with sea urchin-like structures, resolving mentioned issues. The microspheres exhibit a radial microstructure and controllable size, serving as efficient fillers for the easy production of high-performance phase change materials. The microspheres are able to create an efficient interlocking mechanism with surface spike structures, forming a continuous thermal conduction and spatially confined network in the composite material. At a filler content of 43.9 vol%, the thermal conductivity of the Al aerogel microsphere/paraffin composite reaches a peak value of 3.2 W/mK, accompanied by a contact thermal resistance of 1.2 × 10−6 Km2/W. Subjecting the composite to elevated temperatures well above the matrix's phase change temperature preserves its structural stability. This work reports a new structured filler moulding method that supports the development of high performance thermally conductive phase change composites.

Combined effects of sea urchin-like structure and mixed Cu+/Cu0 states on promoting C2 formation in electrocatalytic CO2 reduction

Combined effects of sea urchin-like structure and mixed Cu+/Cu0 states on promoting C2 formation in electrocatalytic CO2 reduction

Facile synthesis of hydroxylated triazine-based magnetic microporous organic network for ultrahigh adsorption of phenylurea herbicides: An experimental and density-functional theory study

Microporous organic networks (MONs) are highly porous materials that are particularly useful in analytical chemistry. However, the use of these materials is often limited by the functional groups available on their surface. Here, we described the polymerization of a sea urchin-like structure material at ambient temperature, that was functionalized with hydroxyl, carboxyl, and triazine groups and denoted as OH-COOH-MON-TEPT. A substantial proportion of OH-COOH-MON-TEPT was intricately decorated EDA-Fe3O4, creating a well-designed configuration (EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC) for superior adsorption of the target analytes phenylurea herbicides (PUHs) via magnetic solid-phase extraction (MSPE). The proposed method showed remarkably low limits of detection ranging from 0.03 to 0.22 ng·L−1. Experimental investigations and theoretical analyses unveiled the adsorption mode between EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC and PUHs. These findings establish a robust foundation for potential applications of EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC in the analysis of various polar contaminants.

M13-Phage-Based Star-Shaped Particles with Internal Flexibility.

We report on the construction and the dynamics of monodisperse star-shaped particles, mimicking, at the mesoscale, star polymers. Such multiarm star-like particles result from the self-assembly of gold nanoparticles, forming the core, with tip-linked filamentous viruses (M13 bacteriophages) acting as spines in a sea urchin-like structure. By combining fluorescence and dark-field microscopy with dynamic light scattering, we investigate the diffusion of these hybrid spiny particles. We reveal the internal dynamics of the star particles by probing their central metallic core, which exhibits a hindered motion that can be described as a Brownian particle trapped in a harmonic potential. We therefore show that the filamentous viruses and specifically their tip proteins behave as entropic springs, extending the relevance of the study of such hybrid mesoscopic analogues of star polymers to phage biotechnology.

Rational design of sea urchin-like FeOOH anchored hollow carbon spheres as chloride-insertion electrodes for efficient faradic capacitive deionization

Faradic capacitive deionization (FDI) is one of the most promising branches of capacitive deionization (CDI) to relieve global water stress. However, the problems of slow desalination kinetics and poor cycle stability of the anode of FDI have greatly restricted the development of its practical applications. Herein, we put forward a strategy of employing hollow carbon spheres (HCSs) with high specific surface area, and good electrical conductivity/stability as the structural backbone and further decorated it with FeOOH nanorod to construct a 3D sea urchin-like structure (HCSs@FeOOH) as the anode for FDI. Notably, the essence of this design is the structural backbone (HCSs) could not only prevent the structural agglomeration between FeOOH but also provide good electric conductivity to the material system to realize superior pseudo-capacitance. As a result, the HCSs@FeOOH-based FDI system displays excellent desalination performance (desalination capacity and rate up to 69.48 mg g−1 and 0.37 mg g−1 s−1) with good durability (only 14.32 % desalination capacity decrease over 100 cycles), respectively.

Sea urchin-like cobalt selenide/N-doped carbon dots as efficient bifunctional electrocatalysts for water electrolysis

Designing high-efficient, durable and low-cost bifunctional electrocatalysts is of great significance to realize green hydrogen production by electrolytic water splitting. Herein, 3D sea urchin-like CoSe2 arrays modified with nitrogen doped carbon dots grown on Ni foam (CoSe2/NCDs/NF) was successfully constructed via an easy hydrothermal reaction combined with anion exchange process. The designed CoSe2/NCDs/NF catalyst exhibits enhanced catalytic activity and stability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in different electrolyte, with reduced overpotential of 268 mV to afford 70 mA cm−2 for OER and low overpotentials of 94/102 mV in acid/alkaline solution at 10 mA cm−2 for HER, respectively. Impressively, when assembling a two-electrode alkaline electrolyzer with CoSe2/NCDs/NF simultaneously acts as the anode and cathode, the cell voltage of only 1.61 V is obtained to drive 30 mA cm−2, with robust stability(for at least 70 h). The excellent catalytic activity is attributed that the 3D sea urchin-like structure significantly augments exposure of active sites and facilitates mass/charge transport; the synergy effect of NCDs and CoSe2 effectively promotes electron transfer, optimizes electronic environment, and adjusts the adsorption/desorption free energy of the intermediates; and in situ growth of materials and introduction of carbon materials ensures structural stability and enhances the electrical conductivity. This work provides a feasible guidance for the rational design of transition metal selenide catalysts with outstanding performance.

In-situ-derived carbon coated sea urchin-like Na3V2(PO4)3 from V2C MXene for high-performance capacitive deionization

Cathode materials with high capacity and cyclic durability are urgently needed for capacitive deionization. Na3V2(PO4)3 is an emerging pseudocapacitive candidate for this process on account of its high capacity and Na+ reversible insertion, while it suffers from the intrinsic low electrical conductivity and small electrolyte-accessible surface area. Herein, a sea urchin-like Na3V2(PO4)3 @carbon (NVP@C) compound material was synthesized from MXene-V2C via hydrothermal method followed by annealing treatment, and then assembled as capacitive deionization (CDI) electrode material. Benefiting from three-dimensional sea urchin-like structure, where the nanoneedles of NVP@C serve as fast transport channel for Na+, NVP@C performed high specific capacity (437 F g−1 at 5 mV s−1) and fast ionic diffusion kinetics. Moreover, the NVP@C showed attractive desalination performance as cathode material for CDI, achieving a remarkable adsorption capacity of 74.0 mg g−1 in a NaCl salt solution (1000 mg L−1) and long life cycle stability. The present work provides a novel perspective to construct practical redox-active and stable CDI electrode with 3D structure from MXene for highly capacitive and durable desalination application.

In situ grown three-dimensional porous Co3O4/graphdiyne oxide hybrid nanomaterials with sea urchin-like structures for high-performance zinc–air batteries

As a promising energy conversion system, zinc air battery (ZAB) usually suffers from short cycle life and poor reversibility due to the slow kinetics of the redox reaction on the air cathode, making it a big-barriers in practical applications. Herein, three-dimensional (3D) porous Co3O4/graphdiyne oxide (GDYO) hybrid nanomaterials with sea urchin-like structures have been prepared by in-situ epitaxial growth. The 3D porous Co3O4/GDYO hybrid nanomaterials with sea urchin-like structures expand the larger contact area between the electrolyte and the electrode, which provide abundant channels for ion diffusion and electron transport with enhanced charge transfer kinetics and structural stability. The 3D porous Co3O4/GDYO hybrid nanomaterials with sea urchin-like structures shows excellent bifunctional electrocatalytic activity for both oxygen evolution reaction (OER) (onset potential of 1.38 V, overpotential of 335 mV at 10 mA cm−2) and oxygen reduction reaction (ORR) (onset potential of 0.84 V, half-wave potential of 0.6 V). ZABs fabricated with 3D porous Co3O4/GDYO hybrid nanomaterials as cathode display a high power density of 96 m W cm−2, an open circuit voltage of 1.53 V, as well as a specific capacity of 799.5 mA h g−1 (at 10 mA cm−2) and a corresponding energy density of 965 Wh kg−1. Further, its charge and discharge voltages remain stable for over 400 h at a constant current charge–discharge cycling of 3 mA cm−2. This work offers novel insights on developing excellent bifunctional electrocatalysts for both OER and ORR, which expands a new application of GDYO on ZABs.

Internally bridged nanosilica for loadings and release of sparsely soluble compounds

The engineering of a new monodisperse colloid with a sea urchin-like structure with a large complex internal structure is reported, in which silica surfaces are bridged by an aromatic organic cross-linker to serve as a nanocarrier host for drugs such as doxorubicin (DOX) against breast cancer cells. While dendritic fibrous nanosilica (DFNS) was employed and we do not observe a dendritic structure, these particles are referred to as sea urchin-like nanostructured silica (SNS). Since the structure of SNS consists of many silica fibrils protruding from the core, similar to the hairs of a sea urchin. For the aromatic structured cross-linker, bis(propyliminomethyl)benzene (b(PIM)B-S or silanated terephtaldehyde) were employed, which are prepared with terephtaldehyde and 3-aminopropyltriethoxy-silane (APTES) through a simple Schiff base reaction. b(PIM)B-S bridges were introduced into SNS under open vessel reflux conditions. SPS refers to the product obtained by incorporating the cross-linker b(PIM)B-S in ultra-small colloidal SNS particles. In-situ incorporation of DOX molecules resulted in SPS-DOX. The pH-responsive SPS nanocomposites were tested as biocompatible nanocarriers for controllable doxorubicin (DOX) delivery. We conclude that SPS is a unique colloid which has promising potential for technological applications such as advanced drug delivery systems, wastewater remediation and as a catalyst for green organic reactions in water.

Simpler and greener preparation of an in-situ polymerized polyimide anode for lithium ion batteries

A simplified and greener procedure for in-situ obtaining polyimide anode materials for lithium-ion battery electrodes is developed. The combined polyimide material synthesis and electrode preparation reduces the number of processing steps and treatment duration and decreases the energy required for heat treatment, solvent evaporation, and organic solvent use. More importantly, polymerization in situ on the electrode surface render the polyimide particles a sea urchin-like structure, leading to fast electrochemical kinetics, and significant improvement in discharge capacity and cycling performance compared with materials obtained using traditional procedures. Specific capacities of 1870 mAh g− 1 and 2277 mAh g− 1 at 30 °C and 60 °C, respectively, are obtained. A capacity of 1774 mAh g− 1 is retained after 500 cycles at high current density of 1000 mA g− 1 at 60 °C. This new preparation process not only simplifies the preparation process and makes it greener, but also significantly improves the battery performance, providing new possibilities for the preparation of high-performance low-cost lithium-ion battery electrodes.

Oxygen deficient sea urchin-like Cu-WO3 with high capacity and long life for anode of lithium-ion battery

Cation-doping and oxygen vacancy (Vo) engineering are powerful strategies to address the low conductivity, sluggish ion kinetics and short cycling life facing in metal oxide. Herein, a series of Cu-doped WO3 with Vo was prepared via a facile hydrothermal method. The results show the ratio of Cu/W plays an important role in morphology regulation and the corresponding electrochemical performance. When the molar ratio of Cu/W is 0.3, the sea urchin-like structured WCu0.3 could be achieved. In this architecture, nanowire is propitious to furnish plentiful transmission channels, paving the way to high rate capability. The sea urchin-like structure with large surface area and rich mesoporous can accommodate the strain during repeat lithiation/delithiation processes, giving rise to high capacity and superior cycling durability. Additionally, the Vo induced by Cu-doping is favorable to the enhancement of conductivity. These combined merits endow WCu0.3 with impressive 1st discharge capacity (1585 mAh g−1 at 0.1 A g−1), good rate capability (621.2 mAh g−1 at 0.1 A g−1 and 520.2 mAh g−1 at 0.5 A g−1) and cycle performance (796.3 mAh g−1 over 300 cycles under 0.5 A g−1). Our work provides a simple approach to optimize metal oxide’s lithium storage performance via Vo regulation by cation-doping.

Highly crystalline carbon nitride with small-sized sea urchin-like structure for efficient photocatalytic hydrogen production under visible-light irradiation

Molten-salt method has been deemed as a feasible strategy to increase the crystallinity of graphitic carbon nitride (abbreviated as CN), thereby improving its photocatalytic activity. However, highly crystalline CN prepared by molten-salt method using bulk carbon nitride (BCN) as the precursor still suffers from a small specific surface area, which is unfavorable to the separation of photogenerated carriers. Here, we report a facile approach to obtain highly crystalline CN with a large specific surface area using tubular carbon nitride (TCN) as raw material, and the final sample is named as tubular carbon nitride-molten salt (TCN-M). Compared with bulk carbon nitride-molten salt (BCN-M) sample, the obtained TCN-M sample not only retains the advantage of high crystallinity, but also exhibits a smaller-sized sea urchin-like structure owing to the CN precursor pretreatment process. The experiment results demonstrate that TCN-M displays an excellent hydrogen production activity of 4.9 mmol g -1 h -1 under visible-light, and its hydrogen production performance can be further enhanced to 14.7 mmol g -1 h -1 after adding 0.5 M K 2 HPO 4 . Thus, this work may supply valuable ideas to further optimize the photocatalytic activity of highly crystalline CN prepared by molten-salt method from the perspective of CN precursor pretreatment. • A highly crystalline carbon nitride with small-sized sea urchin-like structure was successfully prepared. • Large specific surface area and the presence of cyano groups greatly improve the photocatalytic H 2 production activity. • Optimizing the photocatalytic activity of highly crystalline CN from the perspective of CN precursor pretreatment. • A typical H + -reduction cycle can be constructed by introducing K 2 HPO 4 into the reaction system.

Pseudocapacitive boosts nanoparticles composed of sea urchin structure Bi2S3-xSex@rGO with high rate and capacity for sodium ion battery anode

The abundant reserve and low cost of sodium over lithium has prompted an enormous development for sodium-ion batteries(SIBs). SIBs are expected to replace lithium ion batteries in the future and be widely applied. Reliable anodes are one of the key issues in the commercial application of SIBs. Herein, an elaborate sea urchin-shaped Se-doped Bi2S3 (Bi2S3-xSex@rGO) electrode is designed by hydrothermal method for SIBs. The Bi2S3-xSex@rGO electrode exhibits an excellent rate capability (694 mAh g −1 at 2 A g−1)and high reversible capacity (701 mAh g −1 after 100 cycles at 0.1 A g −1), which are superior to those of most Bi2S3 for SIBs anode reported previously. Pseudocapacitive contribution is demonstrated as the main reason of prominent electrochemical performance of the Bi2S3-xSex@rGO electrode. The sea urchin-like structure is composed of bismuth sulfide nanoparticles, which promotes the pseudocapacitance behavior of the electrode. The pseudocapacitance promoted by rapid transport of sodium ions could extend to more advanced SIBs anodes.

Autogenous and Tunable CNTs for Enhanced Polarization and Conduction Loss Enabling Sea Urchin-Like Co3ZnC/Co/C Composites with Excellent Microwave Absorption Performance.

ZIF-67-derived magnetic metal/carbon composites are considered prospective candidates for use as microwave absorption (MA) materials owing to their magnetoelectric synergy. However, the structure of ZIF-67-derived MA materials mainly depends on the morphology and composition of pristine metal-organic frameworks (MOFs), and their microstructures lack a rational design. Herein, a multidimensional sea urchin-like carbon nanotubes (CNTs)-grafted carbon polyhedra-encapsulated Co3ZnC/Co nanoparticle composite was prepared by one-step catalytic pyrolysis of ZIF-67/ZnO using a rational structural design. The autogenous and tunable CNTs obtained with the assistance of zinc evaporation not only overcome the limitation of homogeneous dispersion but also endow the Co3ZnC/Co/C composite with outstanding MA properties owing to the conduction loss provided by CNTs, polarization loss caused by multiple components, and electromagnetic wave trap composed of a special sea urchin-like structure. Consequently, the minimum reflection loss of ZZ0.1-600 reaches -60.3 dB at 1.6 mm, the maximum absorption bandwidth of ZZ0.05-600 is 6.24 GHz (covering nearly the entire Ku band) at 1.9 mm, and the structure has a low weight ratio (30 wt %). Compared with Z-600 and pure ZnO, the MA performance of the sea urchin-like Co3ZnC/Co/C composite obtained by rational structural design has been greatly improved; this strategy offers a new approach for optimizing the MA performance of materials according to their structural design.

Interfacial coupling of sea urchin-like (Mo4O11-MoS2-VO2) 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 (Mo4O11-MoS2-VO2) 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 H2SO4. This electrode needs overpotential of only 43 mV to achieve 10 mA/cm2 with a Tafel slope of 37 mV/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.

Carbon coated nickel cobalt phosphide with sea urchin-like structure by low temperature plasma processing for hydrogen evolution and urea oxidation

Hydrogen production from organic wastewater splitting is a promising approach to reduce electrical energy consumption and remove organic pollutants simultaneously. The key challenge is to develop an effective electrocatalyst with low-cost, high-performance and high-corrosion resistance in harsh environment. Here, a self-supported carbon coated nickel cobalt phosphide grown on nickel foam (CoNiP@C/NF) electrode is synthesized by combining hydrothermal synthesis and plasma processing. Surface coating by graphene-like nanostructure and phosphorization are achieved at mild temperature by low temperature CH4 plasma and Ar-H2-P plasma, respectively, enabling retention of the sea urchin-like structure obtained by hydrothermal reaction. Benefiting from the modulated built-in electric field, the self-supporting CoNiP@C/NF electrode exhibits highly efficient bifunctional catalytic activity for hydrogen evolution reaction (HER) and urea oxidation reaction (UOR), featured for the low voltage of 1.43 V at 20 mA cm−2 of a HER||UOR electrolysis cell. Whether in alkaline solution or organic wastewater, CoNiP@C/NF electrodes could generate H2 continuously and stably for more than 60 h. DFT calculation indicates that Ni doping modifies the surface charge density, which optimizes the adsorption/desorption of intermediates and facilitates the water dissociation during HER. Moreover, CoNiP possesses strong binding with the C layer, thus promoting the structural stability and charge transfer efficiency of the catalyst.

Synthesis and characterization of Mo@Ni core-shell composite powder-reinforced (W,Ti)C-based cermet

To solve the problem of an insufficient solid solution of the metal bonding phase due to the excessively fast sintering rate when preparing cermet by spark plasma sintering (SPS), a Ni-coated Mo (Mo@Ni) composite powder with a uniform morphology and controllable content ratio was prepared by a heterogeneous nucleation-thermal reduction method. Mo@Ni powder with a sea urchin-like structure was then used to prepare (W,Ti)C/Mo@Ni/Co cermet. The results showed that the optimal sintering temperature of (W,Ti)C-based cermet with Mo@Ni was 50 °C lower than that of (W,Ti)C-based cermet with Ni and Mo. The lower sintering temperature inhibited the growth of matrix grains and improved the flexural strength of (W,Ti)C-based cermet. The addition of Mo@Ni also changed the crack propagation mechanism of (W,Ti)C-based cermet, introduced a variety of toughening mechanisms, and improved the fracture toughness. The topotaxy orientation intergrowth structure formed at the grain boundary is similar to the "fence" effect, which is the main reason for the improvement of mechanical properties.

Defect engineering on sea-urchin-like transition-metal oxides for high-performance supercapacitors

Reasonable design of nanostructures and application of Defect Engineering have been proved to be essential for the construction of high-performance electrochemical energy storage devices. Herein, a defect engineering strategy is developed to fabricate a 3D multi-layered sea urchin-like structure assembled by 1D nanowire, which shows a high specific surface area for electrochemical active sites. More significantly, the phosphate-doping treatment introduces N/P elements in P–NiCo2O4, thus generates Co/Ni–P and Co/Ni–N bonds to create more oxygen vacancies. Vacancy defects manipulate the electronic structure of the electrode materials to obtain good physical and electrochemical properties. The prepared sea urchin-like P–NiCo2O4 electrode in this work exhibits exceptionally excellent charge storage capability in aqueous solutions with high specific capacitance (467 C g−1 at 1 A g−1), good rate capability, and ultra-high cycling stability at 20 A g−1 (87.2% capacitance retention over 10,000 cycles). Furthermore, the assembled asymmetric supercapacitor using P–NiCo2O4 cathode and AC anode shows a high energy density of 31.25 Wh kg−1 at a much large power density of 7500 W kg−1, and an outstanding cycling performance at 10 A g−1 (83.4% capacitance retention over 10,000 cycles). The prepared P–NiCo2O4 electrode materials are expected to be used in high-performance supercapacitors.