Urchin-like Architectures Research Articles

Spaced-Confined Janus Engineering Enables Controlled Ion Transport Channels and Accelerated Kinetics for Secondary Ion Batteries.

The large grain boundary resistance between different components of the anode electrode easily leads to the low ion transport efficiency and poor electrochemical performance of lithium-/sodium-ion batteries (LIBs/SIBs). To address the issue, a Janus heterointerface with a Mott-Schottky structure is proposed to optimize the interface atomic structure, weaken interatomic resistance, and improve ion transport kinetics. Herein, Janus Co/Co2P@carbon-nanotubes@core-shell (Janus Co/Co2P@CNT-CS) refined urchin-like architecture derived from metal-organic frameworks is reported via a coating-phosphating process, where the Janus Co/Co2P heterointerface nanoparticles are confined in carbon nanotubes and a core-shell polyhedron. Such a Janus Co/Co2P heterointerface shows the strong built-in electric field, facilitating the controllable ion transport channels and the high ion transport efficiency. The Janus Co/Co2P@CNT-CS refined urchin-like architecture composed of a core-shell structure and the grafting carbon nanotubes enhances the structure stability and electronic conductivity. Benefiting from the spaced-confined Janus heterointerface engineering and synergistic effects between the core-shell structure and the grafting carbon nanotubes, the Janus Co/Co2P@CNT-CS refined urchin-like architecture demonstrates the fast ion transport rate and excellent pseudocapacitance performance for LIBs/SIBs. In this case, the Janus Co/Co2P@CNT-CS refined urchin-like architecture shows high specific capacities of 709 mA h g-1 (200 cycles) and 203 mA h g-1 (300 cycles) at a current density of 500 mA g-1 for LIBs/SIBs, respectively.

Simultaneously tuning the defect and morphology to design urchin-like Fe-Co3O4-x as integrated trapping-catalyzing modified separator for superior lithium-sulfur batteries

The lithium-sulfur (Li-S) battery is a promising candidate for next-generation energy storage devices because of its high energy density and cost-effectiveness. However, its commercial application is still hampered by the severe lithium polysulfides (LiPSs) shuttling and the sluggish polysulfide redox kinetics. Herein, the defect-rich Fe-Co3O4-x with a unique 3D urchin-like architecture has been rationally designed using a microwave-assisted hydrothermal method followed by calcination. The morphology and surface defect of Fe-Co3O4-x are simultaneously regulated by altering the Fe doping content. The resulting Fe-Co3O4-x materials are confirmed with abundant oxygen defects and exhibit strong chemical entrapment towards LiPSs, as evidenced by both the experimental results and the DFT calculations. Under dual regulation, the nanorod-assembled urchin-like architecture could accelerate the electron/ion transport and significantly strengthen the LiPSs redox reaction kinetics. As expected, the assembled Li-S cell with Fe-Co3O4-x modified separator exhibits an ultralow capacity decay of 0.04% per cycle at 1 C after 800 cycles and excellent rate capability as high as 528 mAh g−1 at 5 C. Furthermore, the modification of Fe-Co3O4-x on the separator also improves the reversibility of the lithium anode deposition/stripping. This work provides new insights into effective strategies for designing 3D nanostructural oxygen defect-rich electrocatalysts to achieve advanced Li-S batteries.

Hierarchical and urchin-like chitosan/hydroxyapatite microspheres as drug-laden cell carriers

Biopolymer/hydroxyapatite (HAp) composites are one type of the most promising materials for a variety of biomedical applications. In this study, hierarchical and urchin-like chitosan/HAp nanowire (HU-CS/HAp NW) microspheres were for the first time synthesized by in situ hydrothermal treatment of chitosan/HAp (CS/HAp) microspheres in the acetic acid solution. The results indicate that HU-CS/HAp NW microspheres were spherical in morphology with a diameter of 100–300 μm. Their surface was mainly constructed by numerous HAp NWs with the diameter of 80–120 nm and showed a hierarchical and urchin-like nanofibrous architecture. It was found that the acidic hydrothermal treatment caused an in situ conversion of HAp NPs to HAp NWs. In vitro biocompatible evaluation indicates that HU-CS/HAp NW microspheres showed an enhanced cell attachment and proliferation due to the presence of hierarchical and urchin-like architecture. Furthermore, HU-CS/HAp NW microspheres showed a good adsorption capacity for tetracycline hydrochloride (model drug, one of the most representative antibiotics) with a higher adsorption capacity than CS/HAp microspheres and well maintained their antibacterial efficacy to inhibit the growth of bacteria: Escherichia coli and Staphylococcus aureus. Thus, the present HU-CS/HAp NW microspheres would be applicable as novel drug-laden cell carriers.

Sea urchin-like LiAlO2@NiCoO2 hybrid composites with core-shell structure as high-performance Li storage materials

Sea urchin-like LiAlO2@NiCoO2 hybrid composites with core-shell structure assembled with nanoneedles have been successfully fabricated through a facile hydrothermal route followed by a calcination procedure in N2 for the first time. The sea urchin-like architecture with large accessible surface can offer numerous active sites for redox reaction. The synergy of two advantages has dramatically improved the electrochemical behavior in terms of specific capacity, cycle performance and rate capability, especially at high current densities. The LiAlO2(5.0 wt%)@NiCoO2 displays charge capacities are 1309.0 and 933.6 mAh g−1 at 0.5 and 1A g−1, respectively, after 400 cycles. However, the charge capacities of bare NiCoO2 are only 562.9 and 476.7 mAh g−1 at corresponding rates. Especially, LiAlO2(5.0 wt%)@NiCoO2 preserves 358.1 mAh g−1 after 500 cycles at 2A g−1 with a capacity retention of 74%. The superior electrochemical property is related to the sea urchin-like nature and the ingenious composition design. In addition, the DFT calculation result shows that the formed stable, well-coordinated, and metallic interface between LiAlO2 and NiCoO2 are very helpful for reducing the interfacial impedance and beneficial for the improved rate capability of the materials. Therefore, such LiAlO2@NiCoO2 composites with unique morphology demonstrate a huge potential as electrode materials for Li-ion batteries.

In situ fabrication of urchin-like Cu@carbon nanoneedles based aptasensor for ultrasensitive recognition of trace mercury ion

Mercury ion (Hg2+) is a strong toxic heavy ion that causes severe damages to the environment and readily accumulates in the food chain. However, it remains a major challenge to realize a sensitive and precise recognition of Hg2+ with a trace concentration for early identifying the pollution source. In this work, a novel electrochemical aptasensor was designed to achieve an ultrasensitive and quantitative detection of trace Hg2+, relying on an urchin-like architecture of Cu@carbon nanoneedles (Cu@CNNs) as the electroactive probe. This specific nanostructure was in-situ constructed through a controllable pyrolysis process, serving as a signal magnifier and DNA loading platform owing to its outstanding electrocatalysis and large specific surface areas. Meanwhile, an exonuclease III-assisted cycling amplification strategy was designed to efficiently amplify the signal strength of trace Hg2+via the consecutive release of report probes in nicking reaction. This as-prepared Hg2+ aptasensor exhibited an ultralow detection limit of 3.7 fM (7 × 10−6 ppm) and a wide linear range from 10 fM to 10 μM, together with the satisfactory stability and reusability for assay in real water samples. It is highly expected that this Cu@CNNs based aptasensor will have tremendous potentials in the early warning and efficient pollution monitoring of heavy metal ions.

Morphological Modulation of Conducting Polymer Nanocomposites with Nickel Cobaltite/Reduced Graphene Oxide and Their Subtle Effects on the Capacitive Behaviors.

This work reports on the urchin-like architecture-based nickel cobaltite (NiCo2O4)/reduced graphene oxide (rGO)/conducting polymer [polyaniline (PANI) or polypyrrole (PPy)] nanocomposites prepared through a hydrothermal synthesis procedure, followed by in situ polymerization techniques. Subsequently, these materials are subjected to electrochemical investigation to search for promising electrode materials for energy storage applications. Interestingly, the morphology of NiCo2O4 varies upon the addition of rGO as well as nitrogen-doped rGO (N-rGO). When it is composite with rGO, it forms an urchin-like architecture, and with N-rGO, it forms nanoparticle structures having a diameter of 90 ± 10 nm. Further, these nanostructures are intricately coated by conducting polymers (such as PANI and PPy) as evidenced from the field emission scanning electron microscopy and high-resolution transmission electron microscopy observations, and the overall shape does not alter after the modification. All composites are investigated thoroughly by Fourier transform infrared, Raman, X-ray powder diffraction, and X-ray photoelectron spectroscopies to confer the formation and presence of polymers. The NiCo2O4/rGO/PPy nanocomposites exhibit an excellent specific capacitance of 1547 ± 5 F/g at a current density of 0.5 A/g, a better energy density of 34.37 ± 0.11 W h/kg at 0.5 A/g, a notable power density of 99.98 ± 0.31 W/kg at 0.5 A/g, and retains its 94 ± 1% specific capacitance after 5000 charge-discharge cycles. The uniform coating over the urchin-like architecture by conducting polymers constructs a typical morphology, and possibly, it is the key factor behind gaining such superior electrochemical behavior owing to (a) the enhancement of surface area and (b) the combination of double-layer capacitive and pseudocapacitive properties. Furthermore, a symmetric flexible supercapacitor device made of NiCo2O4/rGO/PPy nanocomposites provides superior electrochemical behavior.

Correction to “SnS Micro/Nanocrystals with Urchinlike Architectures for Capture of Au(III), Pt(IV), and Pd(II)”

Correction to “SnS Micro/Nanocrystals with Urchinlike Architectures for Capture of Au(III), Pt(IV), and Pd(II)”

SnS Micro/Nanocrystals with Urchinlike Architectures for Capture of Au(III), Pt(IV), and Pd(II)

The capture and recovery of precious metals like platinum, palladium, and gold from mine wastewater or secondary resources has raised concerns owing to the necessity and significance of environment...

Urchin-like hierarchical CoZnAl-LDH/RGO/g-C3N4 hybrid as a Z-scheme photocatalyst for efficient and selective CO2 reduction

A unique urchin-like CoZnAl-LDH/RGO/g-C3N4 (LDH/RGO/CN) Z-scheme photocatalyst, which is fabricated by the hydrothermal synthesis of CoZnAl-LDH and the in situ loading of RGO and g-C3N4, is developed for the photocatalytic conversion of CO2. The special spiny external surface and hollow inner cavity endow LDH/RGO/CN with a significantly enhanced light-harvesting capacity. The well-distributed g-C3N4 nanosheets on the CoZnAl-LDH nanoplates, combined with RGO as an electron mediator, constructs an excellent heterosystem with numerous interfaces, efficient charge separation and highly exposed catalytic active sites. The Z-scheme charge-transfer process promotes the oxidizability and reducibility of CoZnAl-LDH and g-C3N4. Furthermore, the synergistic effect among the components contributes to intense adsorption and chemical activation towards CO2, which reduces the reaction barrier for CO2 photoreduction. As a result, the optimized LDH/RGO/CN exhibits highly efficient and selective photocatalytic CO2 conversion to CO. The special 3D urchin-like architecture paves a new way for design of photocatalyst with ideal performance.

Synthesis and characterization of three-dimensional sea urchin-like AgBr/TiO2 microspheres with enhanced antibacterial and visible-light photocatalytic performance

Three-dimensional (3D) AgBr/TiO2 microspheres with remarkable sea urchin-like architectures were prepared by a solvothermal-hydrothermal two-step process. The products have been characterized through XRD, SEM, HRTEM and Nitrogen adsorption–desorption analysis. The antibacterial activity of the 3D AgBr/TiO2 microspheres against Escherichia coli (E. coli) was investigated quantitatively by microcalorimetric method for the first time. Meanwhile, the visible-light photocatalytic performance of the 3D AgBr/TiO2 microspheres was also evaluated for the degradation of rhodamine B (RhB). As a contrast, the same tests were carried out for the conventional AgBr/P25 (TiO2). The results show that the 3D AgBr/TiO2 microspheres prevent better antibacterial and visible-light photoctalytic performance than the conventional AgBr/P25. It revealed that unique morphology effect, the extraordinary visible-light responses of AgBr and various oxidative radicals produced by visible light irradiated 3D AgBr/TiO2 microspheres are responsible for improved antibacterial and photocatalytic performance.

Sea urchin-like Ni–Fe sulfide architectures as efficient electrocatalysts for the oxygen evolution reaction

Nickel–iron sulfides with a sea urchin-like architecture are controllably synthesized and exhibit enhanced OER activities.

3D urchin-like architectures assembled by MnS nanorods encapsulated in N-doped carbon tubes for superior lithium storage capability

With a remarkable advantage of high capacity, manganese sulfides have been considered as promising anode materials for lithium storage. However, they suffer from low electrical conductivity and severe volume variation during charge/discharge process, leading to electrode pulverization and rapid capacity decay. To address these challenges, herein, a three-dimensional (3D) urchin-like composite structure assembled by MnS nanorods encapsulated in N-doped carbon tubes (MnS@NC) has been rationally designed. When evaluated as anode for lithium-ion battery, the MnS@NC composites displayed high reversible capacity (885 mAh g−1 after 400 cycles at 400 mA g−1) and outstanding rate performance (624, 505, 404 and 306 mAh g−1 at current densities of 0.8, 1.6, 3.2 and 6.4 A g−1, respectively). The remarkable electrochemical performance can be ascribed to the unique 3D urchin-like structure and the protection of N-doped carbon tubes, which not only effectively maintain the structural integrity of the electrode, but also improve the electrical conductivity of active material and buffer the volume variation during charge/discharge process.

Bifunctional urchin-like WO3@PANI electrodes for superior electrochromic behavior and lithium-ion battery

A improved bifunctional nanostructure composite was designed and fabricated as reversible electrodes for electrochromic film and lithium-ion battery. This unique optic-electro responsive urchin-like architecture assembled from WO3@PANI nanobelts were prepared by solvothermal and electropolymerization methods. As expected, the composite exhibits the superior optical-electrochemical performances. The composite owns quick switching time ranging from purple, green, yellow, gray to blue via voltage regulation, better rate performance and long-term cycling stability in the galvanostatic charge/discharge process. Benefited from stable structure and short diffusion path, it also demonstrates a distinct optical modulation (△T = 45%) and excellent durability after long-term cycles (1200 cycles). The as-prepared electrode exhibits outstanding cycling stability (capacity retention of 516 mAh g−1 after 1200 cycles with a low average fading capacity of ca. 0.103 mAh g−1 and fading cyclic rate of ca. 0.02% per cycle). The long-term stability studies reveal that urchin-like composite has much more excellent optical and electrochemical durability. The morphology and structure of the composite were carried out by characterization equipment. This effective synthesis strategy will have profound implications for developing the other inorganic–organic nanocomposites in optical and electrochemical field.

Electrochemical measurements of 1D/2D/3DNi-Co bi-phase mesoporous nanohybrids synthesized using free-template hydrothermal method

In this study, a facile and low cost free-template hydrothermal precipitation method was used to synthesize mesoporous Ni-Co based bimetallic carbonates (CO3)2- and/or hydroxides (OH)−micro/nanostructures with different morphologies (1D, 2D and 3D) based on variant stoichiometric compositions. The effect of the growth temperature, synthesis time as well as the Ni/Co-precursors ratio on the physico-chemical properties and faradic electrochemical behavior of these products was investigated. The as-obtained bi-phase nanohybrids were characterized extensively structurally and morphologically. The textural analysis results confirmed the presence of mesoporous products with a BET-SSA ∼50 m2 g−1 (0.52 cm3 g−1 pore volume) for the 3D urchin-like structure and a BET-SSA ∼ 47.14 m2 g−1 (0.31 cm3 g−1 pore volume) was obtained for the 2D nanoflakes structure.The electrochemical measurements performed in a 6.0 MKOH aqueous electrolyte depicted excellent electrochemical performance ascribed to the optimized composition of Ni-Co LDH (or α-Ni(OH)2) with Co2(OH)3Cl and their unique hierarchical mesoporous nanoflake and urchin-like architectures. In addition, an exceptionally notable specific capacitances (capacities) of 1700 F g−1 (161 mAh.g−1) and 1379 F g−1 (192 mAh.g−1) were obtained for both structures at 5 mV s−1 scan rate (0.5 A g−1 gravimetric current density) respectively. These are much better than mono - hydroxides synthesized in same conditions with 351 F g−1 (90 mAh.g−1) for Ni and 216 F g−1 (21.5 mAh.g−1) for Co. A good cyclic stability of ∼98% after 2000 charge-discharge cycles at 30 A g−1 was recorded depicting their potential as suitable materials for energy storage devices.

Plasmon Ag decorated 3D urchinlike N-TiO2−x for enhanced visible-light-driven photocatalytic performance

Plasmon Ag decorated 3D urchinlike N-TiO2−x photocatalysts are successfully synthesized by a facile hydrothermal treatment (180 °C) and combined with a photo-deposition approach, followed by a reduction treatment. The results show that the resultant Ag/N-TiO2−x sample possesses a three-dimensional (3D) urchinlike nanostructure with high crystallinity of anatase. Meanwhile, it exhibits the narrow optical band gap (Eg ∼ 2.61 eV) and the excellent visible-light-driven photocatalytic performance. Moreover, the hydrogen generation rate and photocatalytic degradation rate of phenol are up to 186.2 μmol h−1 g−1 and 97.7% under visible light irradiation, which are about 4.2 and 5.4 folds greater than that of N-TiO2. The mechanism of photocatalytic process is also proposed, and the enhanced photocatalytic property is mainly due to the synergistic reaction of the Ti3+ and N codoping, which narrows the band gap and favors the utilization of visible light, and the plasmon effect of Ag nanoparticles and unique 3D urchinlike architecture, which are propitious to the separation and transmission of photogenerated carriers.

Sea urchin-like architectures and nanowire arrays of cobalt–manganese sulfides for superior electrochemical energy storage performance

Cobalt–manganese (Co–Mn)-based bimetallic compounds (such as Co–Mn oxides, hydroxides) have been investigated as a new type of high-performance electroactive materials for energy storage device. Nevertheless, Co–Mn sulfides are seldom investigated, especially for those with hierarchical architectures and structures. Herein, we first adopt a facile two-step hydrothermal route and synthesize Co–Mn sulfides with sea urchin-like architecture and nanowire array structure. The anion-exchange sulfuration process gives rise to hierarchical structure with numerous nanosheets grown on the surface. Benefiting from the attractive structures and the high electrochemical activity of Co–Mn sulfides, the Co–Mn sulfides show improved performance than Co–Mn oxides with similar morphology. Especially, the Ni foam-supported Co–Mn sulfide nanowire arrays exhibit superior performance of 502 C g−1 at 1 A g−1 as well as excellent cycling stability with 107% of capacity retention after 2000 cycles. In addition, a hybrid supercapacitor Co–Mn sulfide nanowire arrays/RGO displays an energy density of 18.4 Wh kg−1 at 375 W kg−1. More importantly, an ultrahigh power density (22.5 kW kg−1 at 9.5 Wh kg−1) and outstanding cycling stability can also be achieved. The excellent electrochemical performance can be ascribed to the attractive structure and high electrochemical activity of Co–Mn sulfide.

In Situ Ti3+/N-Codoped Three-Dimensional (3D) Urchinlike Black TiO2 Architectures as Efficient Visible-Light-Driven Photocatalysts

In situ Ti3+/N-codoped 3D urchinlike black TiO2 (b-N-TiO2) is synthesized via hydrothermal treatment with an in situ solid-state chemical reduction method, followed by annealing at 350 °C in argon. The results indicate that N and Ti3+ was codoped into the lattice of anatase TiO2. The prepared b-N-TiO2, with a narrow bandgap of ∼2.43 eV, possesses a three-dimensional (3D) urchinlike nanostructure, which is composed of fiberlike architecture with a length of 200–400 nm and a width of 25 nm. The visible-light-driven photocatalytic degradation rate of Methyl Orange and hydrogen evolution rate for b-N-TiO2 are 95.2% and 178 μmol h–1 g–1, respectively, which are ∼3 and ∼8 times higher than those of pristine TiO2. The excellent photocatalytic activity is mainly attributed to synergistic effect of the N and Ti3+ codoping narrowing the bandgap, and unique 3D urchinlike architecture favors the separation and transport of photogenerated charge carriers and offers more surface-active sites.

Nanorods assembled hierarchical urchin-like WO3 nanostructures: Hydrothermal synthesis, characterization, and their gas sensing properties

Self-assembly of one-dimensional nanoscale building blocks into functional 3D complex superstructures has stimulated a great deal of interest. In current work, using a simple CTAB-assisted hydrothermal process, we synthesized the 3D urchin-like WO3 nanostructures with an average diameter of 0.8–1 μm. The urchin-like architectures are assembled by numerous 1D nanorods. The cetyltrimethyl ammonium bromide (CTAB), as an assembling and structure-directing agent, provides nucleation sites for the assembling of the nanorods, and plays a crucial role in controllable synthesis of urchin-like WO3 nanostructures. Meantime, a possible growth mechanism was proposed in detail. The urchin-like WO3 nanostructures showed excellent gas-sensing performances to ethanol at an optimal temperature as low as 350 °C. Such unique 3D architectures may open up an avenue to further enhance the gas-sensing performances of 3D WO3 nanostructures for future sensor application.

Urchin-like Ni-Co-P-O nanocomposite as novel methanol electro-oxidation materials in alkaline environment

A facile one-pot solvothermal method is proposed to fabricate a new series of Ni-Co-P-O compound-based electrocatalysts for methanol oxidation in alkaline environment. It is found that the chemical composition, surface morphology, as well as the crystallographic structure of the final Ni-Co-P-O composites are largely depends on the Co2+/Ni2+ molar ratios in the reaction system. The sample of NiCoPO-2 possessing an urchin-like architecture and a hybrid composition of nano-scaled Ni/Co phosphides and phosphates was produced at a Co2+/Ni2+ molar ratio of 0.18. A larger specific surface area of 540.5m2g−1 and a bimodal pore size distribution are found in the NiCoPO-2 sample. As a potential catalyst, the NiCoPO-2 delivers a highest oxidation current density (∼1567Ag−1) and a good durability (≥20000s) toward the methanol electrooxidation reaction. The superior catalytic performance of the NiCoPO-2 catalyst should be attributed to its unique microstructure and compositions. It is also supposed that the formation of electron tunneling junctions between the metal phosphides and phosphates could provide new channels for facilitating electron transfer throughout the composite electrocatalysts.

Phase- and morphology-controlled synthesis of CdSe microstructures through an effective mixed-solvothermal route

Cubic-phase CdSe (C–CdSe) hollow microspheres and hexagonal-phase CdSe (H–CdSe) urchin-like microstructures have been controllably synthesized through an effective mixed solvothermal method in the absence of any surfactants. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV–Vis absorption spectroscopy and photoluminescence spectroscopy. The volume ratio of ethylenediamine and ethanol of two solvents is a key factor that determines the phase and shape of CdSe crystals. When the volume ratio of ethylenediamine and ethanol is changed from 1:3, through 1:1 to 4:1, CdSe crystals can be changed from hollow spheres (cubic phase), through acanthosphere (mixed phase) to urchin-like architectures (hexagonal phase). Based on the investigation of the influence of solvent ratio on the phase and morphology of CdSe, an “in situ phase transformation and crystal growth” mechanism is proposed. Optical properties indicate that the as-obtained H–CdSe urchin-like microstructures have much stronger optical absorption and emission than C–CdSe hollow microspheres.