Three-dimensional Array Structure Research Articles

Ce-doped NiCo-layered double hydroxide based self-supporting tremella-shaped nanoflower heterostructure as efficient electrocatalyst for the oxygen evolution reaction

NiCo-layered double hydroxide (NiCo-LDH) catalysts, which indicate a profound prospect of oxygen evolution reaction (OER) under alkaline conditions, are facing great challenges in terms of low electrical conductivity, restricted by poor conductivity, limited electrochemical reaction sites, and low-density of edge sites. The authors developed a simple and convenient in-situ one-pot self-assembly method. The Ce-doped defective NiCo-LDH hexagonal nanosheets and nitrogen-doped graphene fabricated the NiCoCe-LDH/RNF electrocatalyst on the nickel foam (NF) substrate, which demonstrated excellent OER activity under alkaline conditions, only needed 299 mV overvoltage to achieve 50 mA cm−2 current intensity, could last for 6 hours at 20 mA cm−2. The highly active OER benefited from the structural advantages of the novelty three-dimensional array structure. The novel geometric structure of tremella-shaped nanoflower integrated with curved nanosheets and curled edges loaded on NF provides more electrochemical reaction sites for intermediate coordination. The nitrogen-doped reduced graphene oxide accommodated better interaction between active materials and charge carriers, enhancing the conductivity and electron transfer performance of nanostructures. The effective synergistic between the heterostructures promoted the excellent OER electrocatalytic activity of NiFeCe-LDH/RNF nanocomposites. DFT calculations at the atomic level of pristine and Ce-doped NiCo-LDH exhibited that Ce-doping can reduce the Gibbs free energy of the potential-determining step and improve the catalytic activity of OER. This work has broadened the horizons for developing simple and highly available OER electrocatalysts.

Biomimetic multi-functional 3D fog collector: Independent of fog flow direction

The shortage of freshwater resources has a great impact on the daily life of human beings, and fog collection has become an effective mitigation measure. In this paper, inspired by the nanofabricated desert beetle, honeycomb, Euphorbia antiquorum L. and cactus, a 3D fog collector combining a conical array structural gradient and a wettability gradient was presented, with special three-dimensional array structure (TA-L/B (PPC)) that ensures that the fog-collecting efficiency of the samples is virtually independent of the direction of the fog flow. The fog collection efficiency of sample TA-L/B (PPC) is close to 4.3 g·h−1·cm−2, a value that is 1.77 times higher than the surface fog collection efficiency of the copper sheet (OS) sample. By rationally designing the surface structure of the sample, the fog circulation process is accelerated, and a sustainable and stable fog collection process is achieved.

Near-infrared Spectrum Characteristics of Micro-Nano Material Based Diffraction Optical Devices

Diffractive optics devices are optical devices in which the amplitude or phase of the incident light is spatially modulated periodically by a micro-nanomaterial based structure. The study of diffractive optics devices in the field of micro and nano can change the spectroscopic behavior of micro and nano diffractive optics devices by varying the microstructure of the structure and the optical wave properties, which can effectively and reasonably modulate the optical wave signal. To study the effect of different parameter structures on the performance of micro-nano diffraction optical devices, in this paper, two three-dimensional array structures of diffractive optical devices are proposed, which are a vertex-intersecting regular tetrahedron structure and a base-intersecting regular frustum structure. Using the Finite-Difference Time-Domain method, the spectroscopic images of the diffractive optics of the constructed micro-nano diffractive devices are studied in the near-infrared band by varying the height of the constructed structures, the type of structures, the wavelength of the incident light waves, and the polarization direction of the light waves in different 3D height coordinates. The effects of different parameter changes on the performance of the micro-nano diffractive optics devices were analyzed by image comparison. The results show that the best diffraction effect is achieved at a structure height of 0.9 μm for both models with different structure types. The study of both structures at this structure height reveals that the location of diffraction occurrence and the intensity of diffraction can be tuned by varying the structure and the relevant parameters such as the polarization of the light wave. This paper has some theoretical applications for the study of high-performance diffractive optics.

Fabrication PANI/NiMn/NMP composite via electrodeposition with an activated process of converse voltage for energy storage

Growing active materials on conductive substrates and constructing three-dimensional structures are indispensable to prepare high energy density supercapacitors. Here, the composite material PANI/NiMn/NMP with a three-dimensional multi-layer structure and polyaniline as the interlayer was prepared on carbon cloth substrate by electrochemical deposition method. The interlayer of polyaniline strengthens the interface between the active material and the conductive substrate, which can effectively improve the cycle stability of the prepared integrated electrode. And the three-dimensional array structure provides abundant active sites and promotes the rapid transport of ions and electrons. NiMn-LDH that has been treated with electrochemical activation and the coating of NiMn phosphate with high conductivity can effectively improve the specific capacitance and cycling stability of the electrode material. The test results show that PANI/NiMn/NMP has high specific capacitance (2013 F g−1) and good cycling stability (retaining 87.38 % of the initial capacity after 5000 cycles). Furthermore, the asymmetric supercapacitor obtained by assembling PANI/NiMn/NMP and activated carbon has an energy density of 41.23 W h kg−1 at a power density of 673.2 W kg−1.

Electronic modulation of CoP nanosheets array by Zn doping as an efficient electrocatalyst for overall water splitting

A zinc-doped CoP nanosheet catalyst (Zn-CoP/CF) grown in situ on a cobalt foam substrate with a three-dimensional array structure, can effectively improve the electrocatalytic overall water splitting performance due to the gradual dissolution of Zn.

Single-Atom Co Doped in Ultrathin WO3 Arrays for the Enhanced Hydrogen Evolution Reaction in a Wide pH Range.

Owing to the scarcity of Pt, low-cost, stable, and efficient nonprecious metal-based electrocatalysts that can be applied in a wide pH range for the hydrogen evolution reaction (HER) are urgently required. Herein, a highly efficient and robust HER catalyst that is applicable at all pH values is fabricated, containing isolated Co-single atomic sites anchored in the self-supported WO3 arrays grown on Cu foam. At a current density of 10 mA cm-2, the HER overpotentials are 117, 105, and 149 mV at pH values of 0, 7, and 14, respectively, which are significantly lower than those of the undoped WO3, suggesting superior electrocatalytic H2-evolution activity at all pH values. The catalyst also exhibits long-term stability over a wide pH range, particularly in an acidic medium over 24 h, owing to the excellent anticorrosion properties of WO3. Density functional theory calculations prove that the enhanced HER activity is attributed to the isolated Co sites because these optimize the adsorption energy of H* species on WO3. Moreover, the high electrical conductivity of Co-doped WO3 and the three-dimensional array structure supported on the porous metal support afford a catalyst with suitable HER kinetics to enhance the catalytic performance.

Smart construction of intimate interface between solid polymer electrolyte and 3D-array electrode for quasi-solid-state lithium ion batteries

Interfacial issues have been the main obstacle to the development of solid-state batteries. In this work, we design a solid hybrid polymer electrolyte based on poly-(ethylene glycol) diacrylate and succinonitrile (PSSE) with a liquid state precursor. An intimate interface between PSSE and Li4Ti5O12@vertical graphene (LTO@VG) electrode with three-dimensional array structure is cleverly constructed by infiltrating fluid precursor of PSSE into vertical pores of LTO@VG followed by polymerization and solidification of PSSE. The quasi-solid-state LTO@VG//PSSE//Li and LiFePO4//PSSE//LTO@VG full cells exhibit superior electrochemical performance since the active materials are closely contacted by the conductive skeleton and ion-conductive electrolyte. The LTO@VG//PSSE//Li cells maintain 85.7% capacity retention after 400 cycles at 2 C and the LFP//PSSE//LTO@VG full cells still reach 99.0% capacity retention after 200 cycles at 0.5 C. This novel strategy for interface engineering paves the way for achieving high-performance solid-state batteries.

TiO2 nanotube/ZnO nanorod/CdS on Ti mesh with three-dimensional array structure for photocatalytic degradation under visible light irradiation

The three-dimensional (3D) TiO2 nanotube arrays (TNTA) were prepared by electrochemical anodization of Ti mesh in a mixed electrolyte solution of (NH4)2SO4 and NH4F. Well-defined CdS-sensitized ZnO nanorod arrays (ZNRA/CdS) were successfully built on TNTA by the hydrothermal method and chemical bath deposition. The as-prepared samples were characterized by means of XRD, FESEM, and UV–Vis. The photocatalytic activities of the samples were evaluated by measuring the photodegradation of methylene blue (MB) in aqueous solution under visible light irradiation. The photocatalytic efficiencies for MB degradation were 49 and 60 % for Ti mesh/ZNRA/CdS and Ti mesh/TNTA/ZNRA/CdS after irradiation for 6 h, respectively. This can be attributed to the presence of TNTA at the bottom of a ZNRA/CdS composite, which provides a direct pathway for photoinjected electrons transferring along the photoanode to enhance charge-collection efficiency and consequently reduce electron–hole recombination. Furthermore, it can enlarge the practical applications range of TiO2 due to its 3D nanoarray structure with good light-harvesting ability and flexibility.

저손실 재구성 분배기를 이용한 빔 성형 배열 안테나 설계

본 논문에서는 새로운 구조의 빔 성형 배열 안테나를 제안한다. 제안된 빔 성형 배열 안테나는 새로운 구조의 저손실 재구성 분배기 및 입체 배열을 통해, 빔 방향 및 빔 폭 제어 특성을 가진다. 여기서, 제안하는 재구성 분배기는 개별 안테나로의 재구성 가능한 RF 전력 분배 기능을 가지고 있기 때문에, 본 안테나에서의 핵심 기술이라 할 수 있다. 또한, 제안된 안테나의 연구 및 특성 입증을 위해, 본 논문에서는 입체형 빔 성형 배열 안테나를 재구성 분배기와 함께 구현하였으며, 실험적으로 RF 전력 분배 모드 제어를 통해 1:1부터 1:N까지 다양한 방사 모드를 가지고 있는 것을 확인하였다. In this paper, new beam-forming array antenna is proposed. The proposed beam-forming array antenna has control ability for beam-direction/width by employing low loss reconfigurable power divide and three-dimensional array structure. The reconfigurable power divider is key idea in the proposed antenna, because it has reconfigurable RF power distribution ability to each antenna. And, for research and verification of the proposed antenna, 3-dimensional beam-forming array antenna is implemented, and the experimental results show that the proposed antenna has various radiation modes from 1:1 to 1:N by adjusting RF power distribution.

N-[(2-Phenyl-2H-1,2,3-triazol-4-yl)methylene]-2-(2-(2-phenyl-2H-1,2,3-triazol-4-yl)-3-{2-[(2-phenyl-2H-1,2,3-triazol-4-yl)methyleneamino]ethyl}imidazolidin-1-yl)ethanamine

The reaction of 2-phenyl-2H-1,2,3-triazole-4-carbaldehyde with triethylenetetramine leads to the formation of a new binucleating ligand, viz. the title compound, C(33)H(33)N(13), demonstrating that this structure has the potential for more flexible rational design and tailoring. The title molecule is rendered quite rigid by the formation of a five-membered imidazolidine ring and there are four independent instances of pi-pi interactions. Both sides of each of the three aromatic arms take part in these interactions, forming a neat three-dimensional array structure.

X-ray and electron-beam lithography of three-dimensional array structures for photonics

The possibility to realize three-dimensional (3D) photonic crystals and the capability to internally insert a waveguide path poses a big challenge from the fabrication point of view. We present a fabrication method for a 3D lattice with designed linear defects by multitilt x-ray exposures and electron-beam lithography. This combination of different lithographies has been developed to control the design and the realization of the linear defects inside the three-dimensional structure. This method has been applied for the fabrication of Nickel Yablonovite lattices with a lattice parameter of 1.8 μm and a total thickness of 15 μm, a value that allows us to achieve a full three-dimensional optical behavior as confirmed by variable angle reflectance measurements.

Three-dimensional array structures associated with Richtmyer-Meshkov and Rayleigh-Taylor instability

A boundary separating adjacent gas or liquid media is frequently unstable. Richtmyer-Meshkov and Rayleigh-Taylor instability cause the growth of intricate structures on such boundaries. All the lattice symmetries [rectangular (pmm2), square (p4mm), hexagonal (p6mm), and triangular (p3m1) lattices] which are of interest in connection with the instability of the surface of a fluid are studied for the first time. They are obtained from initial disturbances consisting of one (planar case, two-dimensional flow), two (rectangular cells), or three (hexagons and triangles) harmonic waves. It is shown that the dynamic system undergoes a transition during development from an initial, weakly disturbed state to a limiting or asymptotic stationary state (stationary point). The stability of these points (stationary states) is investigated. It is shown that the stationary states are stable toward large-scale disturbances both in the case of Richtmyer-Meshkov instability and in the case of Rayleigh-Taylor instability. It is discovered that the symmetry increases as the system evolves in certain cases. In one example the initial Richtmyer-Meshkov or Rayleigh-Taylor disturbance is a sum of two waves perpendicular to one another with equal wave numbers, but unequal amplitudes: a 1(t=0)≠a 2(t=0). Then, during evolution, the flow has p2 symmetry (rotation relative to the vertical axis by 180°), which goes over to p4 symmetry (rotation by 90°) at t→∞, since the amplitudes equalize in the stationary state: a 1(t=∞)=a 2(t=∞). It is shown that the hexagonal and triangular arrays are complementary. Upon time inversion (t→−t), “rephasing” occurs, and the bubbles of a hexagonal array transform into jets of a triangular array and vice versa.