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The density functional theory (DFT) was used to analyze the electron spin competition interaction between next neighbor Ni atoms in various artificially designed structures in a nano-SiC monolayer honeycomb structure. The electronic structural, magnetic and optical properties of a monolayer SiC materials that were doped with different quantities of Ni in a specific shape are detailed in this paper. Interestingly, spin polarization appeared to occur in the structures that were doped with one Ni and 3Ni having a triangular structure. However, there was no spin polarization present in these materials prior to Ni doping, 2Ni doping with a linear structure and 4Ni doping with rhombic structure. The conduction band of the Ni-doped system moved toward the low energy direction which produced a decrease in the band gap. Calculations of the optical properties showed that Ni doping enhanced their photoconduction. It is hoped that the results of this study will have encouraging implications for the application of photoelectric devices and controllable magnetic materials.

Understanding the frictional properties of phosphorene is essential for reliable fabrication and sustainable operation of phosphorene-based nanotechnology devices. Although recent studies have revealed that phosphorene exhibits anisotropic frictional characteristics, the detailed mechanisms are not well analyzed, and the influence of some experimental parameters (e.g., spring stiffness, tip load force, and tip size), which are very sensitive to atomic frictional forces, were not considered. This study was carried out to address the above shortcomings. The anisotropic frictional behavior of phosphorene and its detailed mechanism were analyzed using potential energy profiles. Also, the effects of spring stiffness and tip load force on the stick-slip behaviors were investigated. Furthermore, we studied the sub-nanoscale stick-slip behavior during the nanoscale slip motion. The nanoscale and sub-nanoscale stick-slip phenomena were originated from the tip's behavior of passing over the bond between the phosphorus atoms and over the puckered honeycomb structure along the zigzag and armchair directions. We utilized a simple one-dimensional model to explain the energy profiles. The influence of tip size on the stick-slip behavior was also examined and found related to the initial nanoscale slip velocity. As the tip diameter decreased, a high-frequency sub-nanoscale stick-slip phenomenon and shorter nanoscale slip duration were identified.

Nickel cobalt layered double hydroxide (Ni-Co LDH) is an exciting new electrode material because of its high theoretical capacity and redox activity. However, the complicated synthesis process and the intrinsically low conductivity impede its large-scale commercial application. Hence, a high-efficiency microwave liquid synthesis method was employed to rapidly prepare honeycomb-structured Ni-Co LDH nanosheets on graphene (Ni-Co LDH/G) composite, within minutes range of synthesis time. By introducing graphene, the poor intrinsic conductivity of the Ni-Co LDH could be ameliorated by hybridization effect, as reveled by density functional theory calculations, thus enhancing the rate capability greatly: Ni-Co LDH/G composite retained 87.1% of capacity at high rate, whereas only 50.5% was retained for Ni-Co LDH. In addition, the hybrid supercapacitor with Ni-Co LDH/G//activated carbon could deliver a high energy density of 40.6 Wh kg−1 at 400 W kg−1, along with a stable cycling lifespan with 83.2% of capacity retention after 10,200 cycles. These encouraging findings highlight that microwave synthesis could be an efficient route to engineer coordinating Ni-Co LDH/G composite for advanced electrode materials in supercapacitors.

The rapidly growing demand in wearable electronics has led to the development of transparent flexible conductive electrodes (TFEs) that feature excellent optoelectronic properties. Herein, a facile, eco-friendly and cost-effective strategy of electrospray assisted etching (ESAE) process is presented to fabricate honeycomb-like porous Ag nanowires (NWs) networks. A water-soluble silk fibroin (SF) film served as the mask layer to pattern the Ag NWs networks, on which quasi-periodical distributed holes were simply and spontaneously achieved by electrospraying water droplets to dissolve the SF film. The scale features of the dissolved holes could be adjusted by varying the electrospray parameters, leading to tailored Ag NW networks and customizable figure of merit (FOM). It was found that the quasi-periodic deposition of droplets was assisted by electric field forces. Compared with the fully-coated networks, the optimized porous networks had a well-controlled roughness, improved transmittance of 92.5%, well-maintained conductivity (29 Ω/sq) and excellent mechanical stability, resulting in 9.3% increase in FOM, and could be further customized according to the practical photoelectric demand. The conductivity dropped by only 4.9% after 10,000 bending cycles at a bending radius of 5 mm, demonstrating the good mechanical stability of the honeycomb structures. The simple and nontoxic ESAE process offers an ideal strategy for realizing the trade-off between transmittance and sheet resistance for different optoelectronic applications. Moreover, this strategy has universal scope and would be feasible for large area manufacturing.

Based on the first-principle framework and particle swarm optimization approach, we have predicted two allotropes of arsenic carbide (AsC) monolayers consisting of an equimolar mixture of arsenic and carbon atoms with honeycomb structures, namely as puckered and buckled. Besides excellent stability, they present rich properties that could establish an efficient platform for hole-conductions, optical, and photocatalysis applications. The lower cohesive energy, absence of negative frequencies in the phonon dispersion curve, and ab initio molecular dynamics simulation prove both monolayers are thermodynamically, kinetically, and thermally stable at room temperature. Besides, electronic band structure calculations indicate that puckered and buckled configurations of AsC monolayers possess intrinsic band gaps of 1.27 and 1.78 eV. In particular, the absorption coefficient and bandgap of a puckered configuration are significantly tuned under the uniaxial strain and induces a transition from direct to the indirect gap. The appropriate band edge positions and strong absorption coefficient in the broad visible and ultraviolet light region make both monolayers a promising candidate for photocatalytic water-splitting and next-generation optoelectronic devices. The carrier mobility calculation exhibits both monolayers have the largest hole carrier mobility at room temperature, rendering it for a p-type field-effect transistor.

From the combined experimental and theoretical investigations, we suggest the formation of a honeycomb structure of BeO monolayer on the Mo(112) surface. This structure is matched to the substrate Mo(112), thus giving the (1 × 1) LEED pattern, and its formation is confirmed also by DFT calculations and work function measurements. While a free BeO monolayer is dielectric, the BeO/Mo(112) system is definitely metallic as follows from the bands crossing EF and significant density of states at EF. The honeycomb BeO monolayer is bound to the Mo(112) surface through O atoms situated atop Mo atoms of the surface rows. A substantial rigidity of the BeO monolayer leads to the appearance of empty space above the Mo(112) surface furrows, which may be filled by some gas or water molecules. Hence, this layered system can be very attractive in various applications where porous materials are explored (e.g. for hydrogen storage purposes).

50 μm-thick Fe−Cr−Al metal foils covered by 7 nm-thick Rh overlayers were prepared by pulsed arc-plasma (AP) and r.f. magnetron sputtering technique to compare their catalytic activities. As-prepared metal foil catalysts were wrapped into a honeycomb structure with a density of 900 cells per square inches and the stoichiometric NO−CO−C3H6−O2 reaction was performed at space velocity of 1.2 × 105 h−1. During temperature ramp at 10 °C min−1, honeycomb catalysts showed steep light-off of NO, CO, and C3H6 at above 200 °C and their conversions soon reached to almost 100%. Both catalysts exhibited high turnover frequencies close to or more than 50-fold greater compared with those for a reference Rh/ZrO2 powder-coated cordierite honeycomb prepared using a conventional slurry coating. When the temperature ramping was repeated, however, the catalytic activity was decreased to the different extent depending on the preparation procedure. Significant deactivation occurred only when prepared by sputtering, whereas the sample prepared by AP showed no signs of deactivation. The deactivation is associated with the formation of passivation layers consisting of Fe, Cr, and Al oxides, which covered the surface and decreased the surface concentration of Rh. The Rh overlayer formed by AP was found to be thermally stable because of the strong adhesion to the metal foil surface, compared to the sample prepared by sputtering.

Electrodeposition of silicon from a KF-KCl-KI salt melt at 1000 K using silver and graphite substrates has been studied by the molecular dynamics method. Silicon films of monatomic thickness with a predominantly hexagonal honeycomb structure were obtained on each substrate. The adhesion energy between the obtained film and the silver substrate is 2.5 times higher than that between the film and the graphite substrate. A single cluster grows much faster on a graphite substrate than on a silver substrate, where several clusters are formed at once. As the substrates are filled with silicon, the diffusion coefficient of Si atoms decreases faster on a graphite substrate than on a silver one. The silver substrate is completely covered with silicon, while a three-dimensional Si cluster begins to grow on a graphite substrate incompletely filled with silicon. The obtained silicon films on both substrates do not have the characteristic buckling, which is found in silicene prepared by the chemical vapor deposition on a silver substrate. Films obtained on both substrates have low mechanical stress. The stress distribution in the case of a graphite substrate is more uniform.

The cost of effective preparation of graphene-based nanomaterials is a challenge in high-performance flexible electrodes. We demonstrated the formation of hierarchical porous graphene (HPG) films with defects from polyimide (PI) sheets using a high repetition rate nanosecond fiber laser. The honeycomb structure with mesopores and macropores can be rapidly induced on the polyimide by the localized focused laser beam in air atmosphere. Employing laser direct writing method, the one-step synthesis and patterning of conductive HPG films were achieved directly on the surface of polyimide sheets. The results show that the unique honeycomb porous structure on HPG film is composed of few-layer graphene or graphene stacks. The lattice structure of graphene nanoplatelets contains the Stone-Wales defects. Furthermore, there are a lot of small-size graphene nanoplatelets on the surface of HPG films with high content of edge defects. These two defects can not only enhance the adsorption without compromising on high diffusivity of ions, but also contribute to the infiltration and flow of electrolyte on the surface of electrode. The proposed one-step laser direct writing technique with highly valuable suitable for developing large-scale fabrication of conductive HPG based flexible electrodes at low-cost.

The high performance Ti3C2Tx MXene/natural rubber (NR) composite films with brick–mortar and honeycomb structure are successfully fabricated by a facile pressured-extrusion filtration process and the subsequent curing treatment. The microstructure of the Ti3C2Tx MXene/NR composite films with heterogeneous architectures changed from brick-mortar to honeycomb structures after vulcanization reaction. The brick–mortar structure Ti3C2Tx/NR composite film possesses superior EMI shielding performance with the shielding effectiveness (SE) of 57.1 dB and excellent mechanical properties of a tensile strength of 28.5 MPa. It’s interesting to note that both EMI shielding and mechanical properties of the composite films with honeycomb structure showed significant improvement after curing process compared with those of brick–mortar counterparts, which exhibit the ultrahigh EMI SE of 63.5 dB and optimal mechanical tensile strength of 39.5 MPa. We believe that this work will provides a new idea for the production of high-performance rubber-based EMI shielding materials.

High carbon content and low-priced coal tar pitch (CTP) was a suitable precursor to prepare porous carbon. However, the porous carbon directly prepared by CTP showed an amorphous two-dimensional structure, which limited its subsequent applications in certain respects. In this paper, under the oxidation of H2O during KOH activation, nitrogen and oxygen co-doped three-dimensional honeycomb porous carbons (HPCs) were prepared with carbon disulfide extract of CTP as raw material and melamine sponge as structural framework and nitrogen precursor. HPCs exhibited a unique three-dimensional honeycomb structure, which was able to prevent the stacking of nano materials and provide larger effective specific surface area (2246 m2 g−1) to supply more adsorption space for pollutants in wastewater. In addition, HPC-3, prepared by an impregnation ratio (char:KOH) of 3, displayed excellent adsorption performance of methylene blue, the maximum adsorption capacity was 631.0 mg g−1, which was 2–5 times higher than most of biomass porous carbons previously reported. The adsorption process conformed to Langmuir and pseudo-second order kinetic model. As can be clearly seen from the adsorption results, HPC-3, as a kind of adsorbent, effectively contributed to removing synthetic dyes from wastewater.

Electrochemical energy storage of TiO 2 anodic oxide with a novel honeycomb morphology was characterized and compared with that of standard TiO 2 nanotubes. The new morphology consists of several smaller-diameter (∼20 nm) nanotubes stacked inside of each honeycomb like hemisphere. The honeycomb like hemispheres are 160–200 nm in diameter with inter-wall thicknesses of 20–50 nm grown onto a planar barrier layer. The dual-layered honeycomb oxide has a total thickness of about 350–500 nm and high surface area. Cyclic voltammetry and galvanostatic charge-discharge tests were carried out on these oxide samples in as-anodized and thermally annealed conditions using 0.1 M NaOH and 0.1 M LiCl + 0.1 M HCl electrolytes. The honeycomb arrays showed an areal capacitance of 56 mF cm −2 at 100 mV s −1 scan rate, and 0.75 mF cm −2 at a current density of 0.1 mA cm −2 . The areal capacitance of the honeycomb structured samples were about 60% higher than that of the regular TiO 2 nanotubes. The honeycomb structured TiO 2 also showed 33% higher capacitance retention after 10,000 cycles than that of regular TiO 2 nanotubes. The higher capacitance retention could be attributed to the enhanced structural stability of the honeycomb structures.

In this paper, we compare the cell growth results of NIH-3T3 and Neuro-2A cells over 72 h on flat and honeycomb structured PLA films without and with a two-step atmospheric-pressure nitrogen-based plasma jet treatment. We developed a fabrication system used for forming of a uniform honeycomb structure on PLA surface, which can produce two different pore sizes, 3–4 μm and 7–8 μm, of honeycomb pattern. We applied a previously developed nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet system to treat the PLA film without and with honeycomb structure. NIH-3T3 and a much smaller Neuro-2A cells were cultivated on the films under various surface conditions. The results show that the two-step plasma treatment in combination with a honeycomb structure can enhance cell growth on PLA film, should the cell size be not too smaller than the pore size of honeycomb structure, e.g., NIH-3T3. Otherwise, cell growth would be better on flat PLA film, e.g., Neuro-2A.

Transition metal dichalcogenides (TMDs) caused widespread concern because of their possess graphite-like two-dimensional structure, which allows Na+ reversible de-intercalation between the interlayers and contributes high theoretical capacity. However, the poor conductivity and structural instability greatly limited their application to sodium ion batteries (SIBs). Herein, three-dimensional (3D) honeycomb MoSe2/rGO nanocomposites with outstanding sodium ion storage performance were prepared. The MoSe2/rGO combined the advantages of MoSe2 and rGO. The typical layered structure of MoSe2 provide Na+ diffusion pathways and sufficient active sites, while the rGO increase conductivity and alleviate structural change during Na+ insertion/extraction process. The stable discharge capacity of MoSe2/rGO reaches 300 mAh g−1 at 0.1 A g−1 and retains 247 mAh g−1 after 100 times. It retains a high capacity of 214.7 mAh g−1 at 1 A g−1 and shows outstanding rate capability. The MoSe2/rGO//AC hybrid sodium-ion capacitors (HSIC) achieves a high capacitance of 56.7 F g−1 at 0.1 A g−1, it exhibits an energy density of 87.7 W kg−1 at a power density of 208.8 W h kg−1 and retains 50.5 W h kg−1 when it increases to 1051.4 W kg−1. The article brings up a novel opinion for designing porous TMDs based composites as ideal energy storage materials.

Hierarchical porous carbons (HPCs) were prepared through a simple and friendly method. ZnCl2 was used as an activating agent as well as a catalyst during lignin hydrothermal pre-treatment. The HPCs show a honeycomb structure with abundant micropores and the specific surface area (SSA) of HPCs is in the range of 1097–2955 m2 g−1. The effects of KOH/hydrochar weight ratio and activation temperature on the pore structure and electric double layer capacitor (EDLC) performance of the HPCs were investigated in detail. Compared to hydrothermal carbonization without ZnCl2, the HPCs prepared from hydrothermal pre-treatment with ZnCl2 possess high SSA and specific capacitance (Cs). The sample of 0.5-HPC-600-5 exhibits a high Cs of 384 F g−1 at 40 mA g−1 with 6 M KOH in a two-electrode system as well as excellent cycling stability with 96.96% initial Cs after 10,000 cycles at 2 A g−1. These exciting results show that hydrothermal pre-treatment is an effective route for the preparation of porous carbon with high electrochemical performance from lignin.

Experimental studies have reported several types of Si monolayer structures that are formed on metal surfaces. These structures typically show the topology of a honeycomb bonding network, but differ in terms of corrugation and surface coverage. Using first-principles calculations, we identify atomic-scale mechanisms that underlie the appearance of different configurations as coverage increases during Si deposition on silver. The key point is that any extra Si adatoms that land on preformed silicene films can be incorporated in the honeycomb network and form bonds with underlying Ag atoms. As a result, the corrugation profile changes, giving rise to varying overlayer geometries. We also show that the same set of mechanisms control the appearance of silicene films on an iridium substrate. The results address available experimental data, but also probe the stability and properties of silicene wetting films that have not been observed yet.

Nucleation and growth of C nanoclusters on a dielectric boron nitride (BN) substrate is investigated by first-principles calculations. Monatomic C quantum wires, chemically bonded by one terminal atom to the BN substrate, are found to be stable during the initial growth stage when the number of atoms is less than 10. Monatomic C rings, physically adsorbed on the substrate dominate the second growth stage. The critical number of atoms for quantum rings is 22. Hexagonal honeycomb structures dominate the third growth stage. No critical size is found for hexagonal honeycomb nanoclusters, in contrast to the growth of C clusters on metal surfaces. The stability of hexagonal honeycomb nanoclusters increases with cluster size, and a graphene layer has the highest stability. The presence of C5 ring units has a negative impact on a cluster's stability and also acts as the source of a magnetic moment due to the unpaired 2p electron. 3D-like C cluster structures are not stable on a BN substrate.

By using first-principles pseudopotential calculations, we investigate the magnetic and electronic properties of hydrosilicon honeycomb structure (silicane) with hydrogen vacancies on its surface. It is found that a single vacancy created on the nonmagnetic silicane can induce a magnetic moment of one μB. When a domain of vacancies is considered, the magnetization is determined by the size and geometry of the domain, and whether it is single- or double-sided. Compared with the energy band structure of silicane, the creation of domain causes very flat bands around the Fermi level and tends to reduce the band gap. It is interesting to find that the systems with single-sided domain all exhibit a band gap of about 1.0 eV while those of double-sided domain exhibit strong size dependence.

Anodic porous alumina (APA) films have a honeycomb cell structure of pores and a voltage-induced bi-stable switching effect. We have applied conducting atomic force microscopy (CAFM) as a method to form and to disrupt current paths in the APA films. A bi-polar switching operation was confirmed. We have firstly observed terminals of current paths as spots or areas typically on the center of the triangle formed by three pores. In addition, though a part of the current path showed repetitive switching, most of them were not observed again at the same position after one cycle of switching operations in the present experiments. This suggests that a part of alumina structure and/or composition along the current paths is modified during the switching operations.

Coal-based honeycomb monoliths extruded using methods developed for ceramic materials have been used to retain methylene blue and p-nitrophenol from aqueous solutions. The influence of the filters’ thermal treatment on their textural properties and performance as adsorbents was examined. Characterization by N2 physisorption, mercury porosimetry and scanning electron microscopy along with adsorption tests under dynamic conditions suggest that, depending on the pollutant and its initial concentration, it can be more convenient to previously submit the monoliths to a simple carbonization or to an additional activation, with or without preoxidation, as a consequence of their different resulting pore structures. Infrared spectroscopy indicates that their different adsorption behaviour seems not to be related to differences in their surface chemical groups. In addition, axial crushing tests show that the monoliths have an acceptable mechanical resistance for the application investigated.

Feasibility of growth of InGaAs ridge quantum wire (QWR) hexagonal network structures by atomic hydrogen (H∗)-assisted selective molecular beam epitaxy (MBE) is investigated for use in novel hexagonal quantum circuits based on the binary-decision diagram (BDD) architecture. The fabricated structures were characterized in detail by SEM, AFM, PL and CL measurements. By using patterned substrates with mesa-pattern directions of 〈1 0 0〉– 〈 1 1 0〉 and 〈5 1 0〉– 〈 1 1 0〉 together with optimized H∗-assisted selective MBE, hexagonal networks of the sharp and uniform InGaAs ridge structures were realized down to submicron pitches. Embedded InGaAs QWR hexagonal networks were successfully formed on the ridge structures, giving prospects of realizing a node device density lager than 108 cm−2.

A novel multi-electrode emitter system of the edge-type is proposed. A fine honeycomb structure allows for a large density of emitting units. Such structure may be used as the electron source in e-beam devices. Due to geometry of the elementary structure the impinging ions do not damage the emitting edges.

We have studied the atomic structures formed by monolayer coverages of Au and Ag on the Si(111) surface using primarily the technique of impact-collision ion scattering spectroscopy (ICISS). For the case of Au films annealed at 700°C, three different types of LEED patterns are formed depending on the fractional monolayer coverage: 5 × 1, √3 × √3, and 6×6. The ICISS data reveal that all the three surfaces are structurally similar: the Au atoms reside above the Si(111) plane, most likely in threefold-hollow sites, and the different surfaces appear to be characterized by rows (5×1) or a honeycomb network (√3×√3 and 6×6). In contrast, the Ag films deposited at elevated substrate temperature (480°C) display only a √3×√3 LEED pattern for coverages ranging from 0.25 to 35 monolayers. A trimer model appears to be more consistent with the low coverage Ag ICISS data rather than a honeycomb arrangement of the Ag atoms.

Using the technique of time-of-flight mode impact-collision ion-scattering-spectroscopy, we have studied the structure of two kinds of Ag thin films deposited onto Si(111)7×7 substrates. We have shown that (1) the RT deposited Ag thin film of 10 ML thickness consists of type-A and type-B domains of Ag(111), with type-B being rotated 180° about the surface normal, (2) the experimental ICISS angle scans for the Si(111)√3×√3R30°-Ag surface cannot be explained by the embedded-Ag model proposed so far, (3) the Ag honeycomb structure residing on top of Si is unlikely for the √3 × √3-Ag surface, and (4) both the Ag-trimer and the HCT model, residing on top of Si are more likely, though a clear preference between these two models has not been obtained as yet.