Honeycomb Surface Research Articles

Characterization and Adsorption Capacity Evaluation of ZnCl2 Impregnated Cassava Peel Carbon for Removal of Fe, Ca, Mg and Zn ions in Wastewater from Cassava processing Industry

The objective of this paper was to prepare, characterize and evaluate the adsorption capacity of cassava peel carbon (CPC) impregnation with ZnCl2 salt for the removal of Fe, Ca, Mg and Zn ions in wastewater derived from cassava processing which has been noted to be problematic in terms of management. CPC and cassava peel activated carbon (CPAC) at 1:3, 2:3, and 1:1 impregnation levels were placed in fixed bed adsorption columns to determine metal ion adsorption capacities of the carbon materials after 120, 240, 360 and 480-minute contact times. Langmuir and Freundlich isotherm models were used in assessment of adsorption of the carbon materials, while pseudo-first and second order models were used to validate the adsorption kinetics of Fe, Ca, Mg and Zn. Pore space development was also monitored using scanning electron microscope (SEM) imagery. Results SEM images revealed hexagonal honeycomb surface structure at 2:3 impregnation level and spongy configuration at 1:1 ZnCl2 impregnation level. The correlation coefficient of Langmuir isotherm was observed to be between 0.86 to 1, indicating that the adsorbent is very good in adsorption of the metals, however, Freundlich isotherm is found to be unfavorable in describing CPAC’s capacity in adsorbing zinc ion contaminant. The pH of the carbon materials was observed to have increased while the bulk density reduced with increasing level of impregnation. Conclusively, CPC and CPAC materials are well suited to Langmuir isotherm as well as pseudo-second order model, implying that adsorption occurs well in a monolayer form on the surface material surface.

“Flexible-strong” polylactic acid porous membrane via tailored polymerization degree of lactic acid side-chains grafting for passive daytime radiative cooler

Aerogel possesses the advantages of high specific surface area, low density, and high porosity, which have shown great application in thermal regulation due to its efficient light scattering capability. However, traditional polymer-based aerogels have poor mechanical properties and lack ductility in outdoor applications, the cooling efficiency of the material is easily affected by damage during transportation, installation, and environmental factors. In this work, combining the porous nature of aerogels and the high ductility of membranes, a polylactic acid-based porous membrane cooler was developed by combining a regular honeycomb surface porous structure design and physical/chemical modification to enhance flexibility, using a simple non-solvent induced phase separation method. This porous membrane exhibits both super-flexibility (116 % elongation at break) and porous characteristics. It achieves a sub-ambient temperature decrease of 4–6 °C under direct sunlight. The optimized porous membrane demonstrates high solar reflectance (94 % of peak reflectivity, 90 % of average reflectivity) and strong infrared emissivity (96 % of peak emissivity, 91 % of average emissivity), it also maintains a solar peak reflectivity of 91 % under 100 % tensile strain and 1000 bending cycles, the cooler still maintains a cooling effect of 2–5 °C below ambient temperature. This work paves the way for developing mechanical flexible and strong radiative coolers for thermal regulation.

Distance-Dependent Evolution of Electronic States in Kagome-Honeycomb Lateral Heterostructures in FeSn.

In this work, we demonstrate the formation and electronic influence of lateral heterointerfaces in FeSn containing Kagome and honeycomb layers. Lateral heterostructures offer spatially resolved property control, enabling the integration of dissimilar materials and promoting phenomena not typically observed in vertical heterostructures. Using the molecular beam epitaxy technique, we achieve a controllable synthesis of lateral heterostructures in the Kagome metal FeSn. With scanning tunneling microscopy/spectroscopy in conjunction with first-principles calculations, we provide a comprehensive understanding of the bonding motif connecting the Fe3Sn-terminated Kagome and Sn2-terminated honeycomb surfaces. More importantly, we reveal a distance-dependent evolution of the electronic states in the vicinity of the heterointerfaces. This evolution is significantly influenced by the orbital character of the flat bands. Our findings suggest an approach to modulate the electronic properties of the Kagome lattice, which should be beneficial for the development of future quantum devices.

Investigation of the Multi-Scale Deterioration Mechanisms of Anhydrite Rock Exposed to Freeze-Thaw Environment.

The deterioration of anhydrite rock exposed to a freeze-thaw environment is a complex process. Therefore, this paper systematically investigated the physical and mechanical evolutions of freeze-thawed anhydrite rock through a series of multi-scale laboratory tests. Meanwhile, the correlation between pore structure and macroscopic mechanical parameters was discussed, and the deterioration mechanisms of anhydrite rock under freeze-thaw cycles were revealed. The results show that with the increase in freeze-thaw processes, the mechanical strength, elastic modulus, cohesion, proportions of micropores (r ≤ 0.1 μm), and PT-Ipore throat (0-0.1 μm) decrease exponentially. In comparison, the mass variation, proportions of mesopores (0.1 μm < r < 1 μm), macropores (r ≥ 1 μm), and PT-II pore throat (0.1-4 μm) increase exponentially. After 120 cycles, the mean porosity increases by 66.27%, and there is a significant honeycomb and pitted surface phenomenon. Meanwhile, as the freeze-thaw cycles increase, the frost resistance coefficient decreases, while the damage variable increases. The correlation analysis between pore structure and macroscopic mechanical parameters shows that macropores play the most significant role in the mechanical characteristic deterioration of freeze-thawed anhydrite rock. Finally, it is revealed that the water-rock expansion and water dissolution effects play a crucial role in the multi-scale damage of anhydrite rock under the freeze-thaw environment.

Internal structure of Mycoplasma mobile gliding machinery analyzed by negative staining electron tomography.

Mycoplasma mobile is a parasitic bacterium that forms gliding machinery on the cell pole and glides on a solid surface in the direction of the cell pole. The gliding machinery consists of both internal and surface structures. The internal structure is divided into a bell at the front and chain structure extending from the bell. In this study, the internal structures prepared under several conditions were analyzed using negative-staining electron microscopy and electron tomography. The chains were constructed by linked motors containing two complexes similar to ATP synthase. A cylindrical spacer with a maximum diameter of 6 nm and a height of 13 nm, and anonymous linkers with a diameter of 0.9-8.3 nm and length of 14.7±6.9 nm were found between motors. The bell is bowl-shaped and features a honeycomb surface with a periodicity of 8.4 nm. The chains of the motor are connected to the rim of the bell through a wedge-shaped structure. These structures may play roles in the assembly and cooperation of gliding machinery units.

Investigation on carbon fiber fracture mechanism of honeycomb composites in longitudinal‐torsional ultrasonic‐assisted milling processes

AbstractA multi‐edge micro‐tooth longitudinal‐torsional ultrasonic‐assisted milling (LTUAM) model was established based on the hard brittle characteristics of carbon fiber honeycomb composites and the weak strength characteristics of the hole wall interface. The study analyzed the effects of ultrasonic characterization parameters on the cutting force, honeycomb wall width, and surface morphology. The results indicate that using LTUAM significantly reduced the cutting force and decreased the length and height of the burrs at an appropriate ultrasound amplitude. The spindle speed had the least impact on the width of the honeycomb wall, but increased with the longitudinal‐torsional ultrasonic amplitude and feed rate. The maximum error between the simulated and experimental cutting force values was approximately 19%. The longitudinal amplitude and torsional amplitude were 3 and 5 μm, respectively, the length of burrs decreased by 52.7%, and there was less delamination and tearing damage. LTUAM proved to be beneficial in improving cutting performance. Compared with conventional milling (CM), LTUAM resulted in regular fiber fracture morphology and smaller fragments on the honeycomb surface. In addition, the high‐frequency ultrasonic vibration promoted carbon fiber fracture and the surface roughness value under LTUAM was approximately 36.72% smaller than that of CM.Highlights Ultrasonic milling mechanism of carbon honeycomb is studied. Kinematic simulation of the tool of carbon honeycomb was studied during LTUAM. LTUAM promotes the fracture of carbon fibers. A multi‐edge micro‐tooth LTUAM model was established of carbon honeycomb. Deformation of the cell wall can be avoided by ultrasonic vibration of the cutter.

A method to in-situ synthesize surface coating of SiC nanowhiskers on cordierite honeycombs by combining aluminothermic, silicothermic and carbothermic reduction reactions

A simple in-situ method was proposed to synthesize surface coating of SiC nanowhiskers on cordierite honeycombs by aluminothermic, silicothermic, and carbothermic reduction reactions. The surface coating of SiC nanowhiskers was synthesized by controlling the partial pressure of SiO gas on the surface of honeycombs, based on the pore-forming process using aluminium(Al) agent. Increasing the porosity of the honeycombs provided aisles to volatilize SiO gas, and the growth of SiC nanowhiskers changed from inside the honeycomb wall to on the honeycomb surface. SEM and TEM observations revealed that the relatively high porosity (≥45%) and sintering temperature (1250–1300 °C) were necessary for obtaining surface coating of SiC nanowhiskers, and the nanowhisker-coating having the smooth morphology and a thickness of ∼150 µm was obtained at 1250 °C. Compared with cordierite honeycombs without SiC nanowhiskers, SiC nanowhiskers inside the honeycomb walls could improve the compressive strength and thermal conductivity with increasing rates of 121% and 123%, respectively, and the surface coating of SiC nanowhiskers increased the specific surface area of the honeycombs by 241 times.

Three-Dimensional Reconstruction of Railway Bridges Based on Unmanned Aerial Vehicle–Terrestrial Laser Scanner Point Cloud Fusion

To address the incomplete image data collection of close-to-ground structures, such as bridge piers and local features like the suspension cables in bridges, obtained from single unmanned aerial vehicle (UAV) oblique photography and the difficulty in acquiring point cloud data for the top structures of bridges using single terrestrial laser scanners (TLSs), as well as the lack of textural information in TLS point clouds, this study aims to establish a high-precision, complete, and realistic bridge model by integrating UAV image data and TLS point cloud data. Using a particular large-scale dual-track bridge as a case study, the methodology involves aerial surveys using a DJI Phantom 4 RTK for comprehensive image capture. We obtain 564 images circling the bridge arches, 508 images for orthorectification, and 491 images of close-range side views. Subsequently, all images, POS data, and ground control point information are imported into Context Capture 2023 software for aerial triangulation and multi-view image dense matching to generate dense point clouds of the bridge. Additionally, ground LiDAR scanning, involving the placement of six scanning stations both on and beneath the bridge, was conducted and the point cloud data from each station are registered in Trimble Business Center 5.5.2 software based on identical feature points. Noise point clouds are then removed using statistical filtering techniques. The integration of UAV image point clouds with TLS point clouds is achieved using the iterative closest point (ICP) algorithm, followed by the creation of a TIN model and texture mapping using Context Capture 2023 software. The effectiveness of the integrated modeling is verified by comparing the geometric accuracy and completeness of the images with those obtained from a single UAV image-based model. The integrated model is used to generate cross-sectional profiles of the dual-track bridge, with detailed annotations of boundary dimensions. Structural inspections reveal honeycomb surfaces and seepage in the bridge piers, as well as painted rust and cracks in the arch ribs. The geometric accuracy of the integrated model in the X, Y, and Z directions is 1.2 cm, 0.8 cm, and 0.9 cm, respectively, while the overall 3D model accuracy is 1.70 cm. This method provides technical reference for the reconstruction of three-dimensional point cloud bridge models. Through 3D reconstruction, railway operators can better monitor and assess the condition of bridge structures, promptly identifying potential defects and damages, thus enabling the adoption of necessary maintenance and repair measures to ensure the structural safety of the bridges.

A new route of production of the meso-porous chitosan with well-organized honeycomb surface microstructure from shrimp waste without destroying the original structure of native shells: Extraction, modification and characterization study

The highly active bio-polysaccharide based compound namely chitin and chitosan have been extracted from shrimp shell which usually expelled out extensively from food processing industries and considered as waste materials. However, by conducting demineralization, de-proteinization and deacetylation on it which could be a new route of production of valuable meso-porous chitosan that possesses a noteworthy well-organized honeycomb like surface microstructure which undoubtedly capable to form sustainable bio-composites. Whereas the honeycomb like microstructures showed a well-defined pore canals (Pc) and pore canal tubes (Pct) onto their surface. The samples were characterized via ATR-FTIR spectroscopy, High resolution SEM, AFM, EDX, XRD and 13C solid-state Cross-Polarization Magic Angle Spinning (CPMAS) NMR. The molecular weight(M‾v) of isolated chitin and chitosan were determined by viscosity and the values were 1.06 × 106(DPv = 5228), 1.8 × 104(DPv = 116) respectively besides degree of deacetylation (DDA) were measured by ATR-FTIR spectroscopy, CPMAS NMR, pH-metric titration and the values were 24&21 for chitin and 84&82 for chitosan. The results suggest that the shrimp shell waste is an attractive source of well-organized honeycomb like meso-porous chitin and chitosan with regular surface microstructures which might have a significant/potential application into the sustainable bio-composite formulation due to various industrial and biomedical sector indeed.

Elaborately designed 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures as advanced microwave absorbers

Microwave absorption materials with lightweight, high absorption performance, and a broad absorption bandwidth are becoming increasingly popular due to the rapid advancements in wearable devices and portable electronic products. The two-dimensional Ti3C2Tx MXene is a highly promising electromagnetic shielding material thanks to its excellent conductivity, rich functional groups and customizable surface chemistry. However, the low dielectric loss of this material restricts its applications in microwave absorption. Herein, 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures were synthesized by simple hydrothermal and secondary annealing methods. Vertically assembled MoS2 nanosheets ensured a large electromagnetic energy storage capacity and promoted additional interfacial polarization. The honeycomb surface structure facilitated the electromagnetic wave attenuation through multiple reflections. The carbon coating and M−Ti3C2Tx matrix resulted in high conductive loss in the final products. The three-dimensional honeycomb M−Ti3C2Tx@MoS2@C heterostructures demonstrated exceptional microwave absorption performance. When filler loadings reached 40 wt%, the 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures delivered a minimum reflection loss of −47.55 dB at a thickness of 4.0 mm, with the added benefit of increasing the effective absorption bandwidth to 4.02 GHz. These findings paved the way for the commercialization of advanced microwave absorbers.

A 2D Bismuth-Induced Honeycomb Surface Structure on GaAs(111).

Two-dimensional (2D) topological insulators have fascinating physical properties which are promising for applications within spintronics. In order to realize spintronic devices working at room temperature, materials with a large nontrivial gap are needed. Bismuthene, a 2D layer of Bi atoms in a honeycomb structure, has recently attracted strong attention because of its record-large nontrivial gap, which is due to the strong spin-orbit coupling of Bi and the unusually strong interaction of the Bi atoms with the surface atoms of the substrate underneath. It would be a significant step forward to be able to form 2D materials with properties such as bismuthene on semiconductors such as GaAs, which has a band gap size relevant for electronics and a direct band gap for optical applications. Here, we present the successful formation of a 2D Bi honeycomb structure on GaAs, which fulfills these conditions. Bi atoms have been incorporated into a clean GaAs(111) surface, with As termination, based on Bi deposition under optimized growth conditions. Low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/S) demonstrates a well-ordered large-scale honeycomb structure, consisting of Bi atoms in a √3 × √3 30° reconstruction on GaAs(111). X-ray photoelectron spectroscopy shows that the Bi atoms of the honeycomb structure only bond to the underlying As atoms. This is supported by calculations based on density functional theory that confirm the honeycomb structure with a large Bi-As binding energy and predict Bi-induced electronic bands within the GaAs band gap that open up a gap of nontrivial topological nature. STS results support the existence of Bi-induced states within the GaAs band gap. The GaAs:Bi honeycomb layer found here has a similar structure as previously published bismuthene on SiC or on Ag, though with a significantly larger lattice constant and only weak Bi-Bi bonding. It can therefore be considered as an extreme case of bismuthene, which is fundamentally interesting. Furthermore, it has the same exciting electronic properties, opening a large nontrivial gap, which is the requirement for room-temperature spintronic applications, and it is directly integrated in GaAs, a direct band gap semiconductor with a large range of (opto)electronic devices.

PtS2 metamaterials: Fabrication and physical properties

Metamaterials are electromagnetic materials with engineered sub-wavelength structures, which can be coupled with the incident electromagnetic wave to produced peculiar physical properties. Currently, many studies are being conducted to the transition metal dichalcogenides (TMDs) due to their unique structures and novel physical properties. Here, we produced honeycomb nanostructure with various sizes on few-layer PtS2 through a well-developed nanosphere lithography technology. In this way, the unique properties of PtS2 metamaterials can be tuned to explore more exotic physical characteristics. The honeycomb surface morphology of PtS2 metamaterials has been demonstrated using the scanning electron microscope and the atomic force microscope. The optical absorption spectra of Pt and PtS2 metamaterials were investigated and the results show that the absorption spectra can be modulated by changing the size of the nanostructure. In addition, the optical anisotropic properties of Pt and PtS2 metamaterials were characterized through the angle-resolved absorption spectra. Raman spectroscopy shows the surface-enhanced Raman spectroscopy (SERS) effect of Pt metamaterials. The simulation exhibits the electric field distribution of PtS2 metamaterials at different wavelengths. The results offer a new approach to develop novel optoelectronic devices based on the meta-structure of TMDs.

Influence of modified graphene oxide on the antifouling performance of waterborne polyurethane coatings containing amphiphilic honeycomb surface

Influence of modified graphene oxide on the antifouling performance of waterborne polyurethane coatings containing amphiphilic honeycomb surface

Towards an Ideal Energy Absorber: Relating Failure Mechanisms and Energy Absorption Metrics in Additively Manufactured AlSi10Mg Cellular Structures under Quasistatic Compression

A designer of metallic energy absorption structures using additively manufactured cellular materials must address the question of which of a multitude of cell shapes to select from, the majority of which are classified as either honeycomb, beam-lattice, or Triply Periodic Minimal Surface (TPMS) structures. Furthermore, there is more than one criterion that needs to be assessed to make this selection. In this work, six cellular structures (hexagonal honeycomb, auxetic and Voronoi lattice, and diamond, gyroid, and Schwarz-P TPMS) spanning all three types were studied under quasistatic compression and compared to each other in the context of the energy absorption metrics of most relevance to a designer. These shapes were also separately studied with tubes enclosing them. All of the structures were fabricated out of AlSi10Mg with the laser powder bed fusion (PBF-LB. or LPBF) process. Experimental results were assessed in the context of four criteria: the relationship between the specific energy absorption (SEA) and maximum transmitted stress, the undulation of the stress plateau, the densification efficiency, and the design tunability of the shapes tested—the latter two are proposed here for the first time. Failure mechanisms were studied in depth to relate them to the observed mechanical response. The results reveal that auxetic and Voronoi lattice structures have low SEA relative to maximum transmitted stresses, and low densification efficiencies, but are highly tunable. TPMS structures on the other hand, in particular the diamond and gyroid shapes, had the best overall performance, with the honeycomb structures between the two groups. Enclosing cellular structures in tubes increased peak stress while also increasing plateau stress undulations.

A form error evaluation method of honeycomb core surface

Form error evaluation of the machined honeycomb surfaces has the power to deliver tremendous benefits to improve the machining accuracy and guide the assembly process. The line laser measurement can meet the high-resolution requirement for thin-walled honeycomb cell walls, but faces a high proportion of noise data consisting of burrs and outliers. In this paper, dimensionality reduction combined with random sample consensus or regression analysis is adopted to distinguish the irregular noise from the measurement data. A directional extraction of honeycomb core surface form based on locally weighted regression is proposed. A highly realistic honeycomb surface simulation method is established to solve the lack of honeycomb benchmarks. The simulation experiment shows that the accuracy of the proposed method is ±7 μm. The comparison experiment with coordinate measuring machine demonstrates the surface form RMS error differences for the polygonal and curved honeycomb by the two method are 7 μm and 19 μm, respectively.

Apparent Quality and Service Performance Evaluation of SCFFC in Tunnel Secondary Lining

After removing the mold from the secondary lining concrete of a tunnel, problems such as honeycomb and hemp surface easily occur. To obtain self-compacting fair-faced concrete (SCFFC) that can meet strength requirements and effectively solve the above problems, this research prepared SCFFC with different mix proportions and performed slump expansion, slump, J-ring expansion and mechanical tests. Additionally, this research comprehensively analyzed the SCFFC based on fuzzy mathematics to study its apparent quality and service performance. This research aimed to solve problems such as uneven bubbles and poor bubble diameter in C30 SCFFC, through a combination of defoaming and air entraining by adding defoamer and air-entraining agent according to different proportions for compound treatment. The defoamer dosage was 0.5‰ of that of water reducer, and the air-entraining agent dosage was 0.1‰ of that of cement. The workability and clearance passability of the concrete were optimal. At the same time, the apparent holes in the SCFFC were small, as were their area and quantity. The distribution and apparent color of the SCFFC were uniform. Considering the factors affecting the service performance of concrete and after a comprehensive analysis of the samples’ weights, subjection degree, variability, stability, and strength index, this research found that the ratio for obtaining a C30 SCFFC material with the highest apparent quality and service performance was as follows: cement:machine-made sand:crushed dtone:fly-ash:water = 4:8.6:9.3:1:2.2. The water reducer comprised 1.0% of the total mass of the cementitious materials. The defoamer dosage was 0.5‰ of that of water reducer, and the dosage of air-entraining agent was 0.1‰ of that of cement.

A new criterion to evaluate the machined surface quality of the Nomex® honeycomb materials

The use of sandwich structures based on composite and/or metallic honeycomb core has grown considerably these last years, especially for aeronautic, aerospace, naval and automotive fields. The proposed work deals with the analysis of milling Nomex® honeycomb core that usually generates poor machined surface quality and problems in assembling parts. The performance of milling process and obtained surface quality are strongly influenced by the honeycomb material properties and cutting parameters. The composite nature of the Nomex® paper forming the honeycomb structure, the thin wall thickness and its alveolar shape make the use of conventional parameters of quantifying the surface quality (as roughness) inappropriate. In this study a new method of measurement of the surface quality has been developed. This innovative approach allows simultaneously the identification and quantification of induced machining defects, as well as the evaluation of the performance of the obtained surface. A new quality criterion was then carried out to obtain the best compromise between high surface quality and optimal cutting conditions. This will improve the use of honeycomb materials in sandwich assemblies for industry. • Analysis of machining Nomex honeycomb with specific cutting tools • Obtained surface quality is strongly influenced by honeycomb material properties and cutting parameters. • Identification of a new criterion for the machined honeycomb surface evaluation • A new quality criterion makes able to choose the optimal cutting conditions.

Decomposition of Hydroxylammonium Nitrate Solution Over Nanoporous CuO Supported on Honeycomb.

We investigated the influence of a copper loading strategy over a honeycomb structure on the catalytic performance during the decomposition of a hydroxylammonium nitrate (HAN) aqueous solution. Copper was supported on the honeycomb surface by means of a metal coating method (MC), i.e., a method of directly coating a metal, and a metal alumina coating method (MAC), i.e., a method of coating a mixture of metal and alumina. The properties of the catalysts were analyzed by N₂ adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The Cu(16.8)/honeycomb-MC catalyst showed a lower decomposition onset temperature during the decomposition of the HAN aqueous solution compared to that over the Cu(7.0)/honeycomb- MAC catalyst, an outcome ascribed to the higher copper loading and the higher dispersion of copper in the Cu(16.8)/honeycomb-MC catalyst compared to that in the other catalyst. The Cu(16.8)/honeycomb-MC catalyst was confirmed to have both excellent activity and heat resistance during the decomposition of a HAN aqueous solution.

Nano-oxides washcoat for enhanced catalytic oxidation activity toward the perovskite-based monolithic catalyst.

In order to explore a superior washcoat material to give full play to the catalytic activity of perovskite active components on the monolithic catalysts, three novel types of LaCoO3/washcoat/cordierite monolith catalysts were prepared by a facile two-step procedure which employed the cordierite honeycomb ceramic as the monolith substrate, the nano-oxides (ZrO2, ɤ-Al2O3, TiO2) as the washcoat, and the perovskite of LaCoO3 as the active components. The blank cordierite, powdered LaCoO3, semi-manufactured monolithic catalysts (washcoat/cordierite), and manufactured monolithic catalysts (LaCoO3/washcoat/cordierite) were characterized by XRD, SEM, XPS, N2 adsorption-desorption, H2-TPR, and ultrasonic test, and their catalytic activities and catalytic stability were evaluated by the toluene oxidation test. The research results indicate that the nanoparticles coated on the cordierite substrate as the washcoat can give full play to the catalytic ability of the LaCoO3 active components and also showed high catalytic stability. However, the catalytic properties of the monolithic catalysts vary notably with the species of nano-washcoat. Among all the catalysts, the porous honeycomb surface structure, uniform distribution, high ratio of surface adsorbed oxygen, and strong reducing ability together give the LaCoO3/ZrO2/cordierite monolithic catalyst the highest catalytic activity on the oxidation of toluene at low temperature, which could be attributed to the excellent interactions of perovskite and nano-ZrO2 washcoat. Therefore, the nano-oxides, especially the nano-ZrO2, have a broad practical application potential for toluene oxidation at low temperature as the washcoat of perovskite-based monolithic catalysts.

Sandwich-structural Ni/Fe3O4/Ni/cellulose paper with a honeycomb surface for improved absorption performance of electromagnetic interference

Highly efficient shielding materials with an excellent electromagnetic wave absorption have gained increased attention. A new design was used to provide cellulose paper with a high electromagnetic shielding effectiveness (EMI SE) and improve the absorption performance by constructing an asymmetry sandwich structure that consisted of a dense nickel coating, Fe3O4 nanoparticles and a porous nickel layer. This unique structure caused a “multiple reflection-absorb-reflection” process when the electromagnetic waves penetrated the sample. The EMI absorption (SEA) and total SE (SET) increased with Fe3O4 absorption time increasing at 8.2–12.4 GHz, which was attributed to the synergistic effect between porous nickel layer and Fe3O4 nanoparticles. The SEA and SET of the sample with a thickness of 0.195 mm can achieved 18.57 and 41.88 dB, respectively. The design was conducive to improving the magnetic and corrosion resistance properties. This study provided a novel path to obtain a low cost and lightweight electromagnetic shielding material that can reduce secondary radiation.