Coral-like Structure Research Articles

Anticorrosion Superhydrophobic Surfaces on AA6082 Aluminum Alloy by HF/HCl Texturing and Self-Assembling of Silane Monolayer

In this paper, the tailoring of superhydrophobic surfaces on AA6082 aluminum alloy by chemical etching in an HF/HCl solution, followed by silane self-assembling, was applied for enhanced corrosion protection in the marine field. In particular, different etching times were considered in order to optimize the treatment effect. The results indicate that all the prepared surfaces, after silanization, were characterized by superhydrophobic behavior with a contact angle higher than 150°. The contact and sliding angles strongly depend on the surface morphology at varying etching times. The optimum was observed with an etching time of 20 s, where a microscale coral-like structure coupled with a homogeneous and ordered pixel-like nanostructure was obtained on the aluminum surface showing a Cassie-Baxter superhydrophobic behavior with a water contact angle of 180° and a sliding angle equal to 0°. All superhydrophobic surfaces achieved an enhanced corrosion protection efficiency and impedance modulus up to two orders of magnitude higher than the as-received AA6082 in simulated seawater.

Improved hydrogen production performance of Ni–Al2O3/CaO–CaZrO3 composite catalyst for CO2 sorption enhanced CH4/H2O reforming

Bifunctional composite catalysts are very intrigued to produce hydrogen via CO2 sorption enhanced CH4/H2O reforming. However, their hydrogen production performance declined over multiple cycles, owing to the structure collapse and the sintering of active component under high-temperature regeneration. This work reported the facile synthesis of long-lasting Ni–Al2O3/CaO–CaZrO3 composite catalysts with less inert components (36 wt%) for stable hydrogen production over the multiple cycles of CO2 sorption enhanced CH4/H2O reforming. The effects of reaction and regeneration temperature on the hydrogen production performance of Ni–Al2O3/CaO–CaZrO3 were explored. Ni–Al2O3/CaO–CaZrO3 demonstrated high activity and stability while fixing reaction temperature as 600 °C and regeneration temperature as 750 °C. Of particular importance, H2 concentration was 98 vol% even after 10 hydrogen production cycles due to the inert component CaZrO3 having a cross-linked structure. The distribution of CaZrO3 in the composite as a coral-like structure inhibited the sintering of CaO through high Taman temperature and physical separation. Moreover, it provided the skeleton support and pore volume for the repeated expansion and contraction process of CaO to CaCO3 during the cycling process. Finally, the sintering of Ni slowed down in appropriate regeneration temperature to maintain the structure of the composite catalyst, which further improved the catalyst's stability over multiple cycles.

Pt–Ru bimetallic nanoparticles anchored on carbon nanotubes/polyaniline composites with coral-like structure for enhanced methanol oxidation

In order to surmount the poor stability and low utilization efficiency of Pt catalysts, the Pt-Ru bimetallic nanoparticles/polyaniline/multi-walled carbon nanotube composites (PRPM) were fabricated. Structural characterization data by transmission electron microscope, scanning electron microscope, spherical aberration corrected transmission electron microscope, X-ray photoelectron spectroscopy analysis revealed PRPM with coral-like structure. The particle size of Pt-Ru bimetallic nanoparticles were about 3.76 nm. It exhibited higher mass activity of Pt 10 Ru 1 /PANI/CNTs catalyst (987.9 mA·mgPt −1 ) compared to Pt 10 Ru 1 /CNTs catalyst (619.2 mA·mgPt −1 ) for MOR. The Pt 10 Ru 1 /PANI/CNTs catalyst showed lower onset potentials, lower peak current potential compared to Pt-Ru/C in CO stripping experiment. The calculated results were confirmed by the above experimental data. This work provided scientific guidance for fabricating new functional materials in fuel cells field. • The Pt-Ru/polyaniline/carbon nanotubes composites have coral-like structure. • The Pt 10 Ru 1 /PANI/CNTs catalysts had the lower potential and higher current density for MOR. • The prepared composites showed higher performance in methanol and CO oxidation. • The prepared bimetallic catalysts are potential candidate for MOR.

Improvements in Brazed-Joint Properties of Silicon Nitride and Titanium Alloys Using Laser-Induced Microscale Rice Leaf Structures.

Si3N4 ceramics with a microscale rice leaf structure (MRLS) and titanium alloy were connected via brazing, and the influence of the surface microstructure on the ceramic connection was analyzed. MRLS fabrication is an efficient and high-degree-of-freedom method that can be used to change a material’s surface morphology and wettability. The MRLS was obtained at a laser power of 110 W, with line spacings of 100 and 50 μm. The laser-treated surface included nanoparticles and micro particles, exhibiting a coral-like structure after agglomeration. When the MRLS was used to braze the titanium alloy, no defects were observed at the brazing interface, and the formation was excellent. Throughout the brazed joint, the MRLS remained intact and formed a strong metallurgical bond with the brazing filler metal. A finite element analysis was performed to study the cross-sectional morphology after joint fracture; from the load-time curve, it was found that the MRLS on the surface not only helped improve the mechanical occlusion and brazing area at the interface, but also helped generate compressive stress on the Si3N4 side. Crack propagation was hindered, thereby increasing the joint strength.

Role of dermoscopy in diagnosing and differentiating seborrheic keratoses

Background Seborrheic keratosis is one of the most common benign epidermal tumors seen in elderly individuals. It has slow growth and presents with a varied degree of pigmentation in skin color closely resembling many other pigmented dermatoses. Dermoscopy, a noninvasive technique, could increase the accuracy of diagnosis and can differentiate it from various closest mimickers and malignancies. Aim This study aims to describe the various dermoscopic features of seborrheic keratosis in a series of cases. Patients and methods A hospital-based, descriptive study was conducted over 12 months from January 2018 to December 2018 in the Department of Dermatology, a tertiary-care center. A total of 100 patients were selected and evaluated in a prestructured proforma concerning age, sex, site of lesion, number and duration, and associated comorbidities. The lesion is observed on dermoscopy, and the dermoscopic patterns were then documented and analyzed. Result Among a total of 100 (32%) cases, the most common age group was between 41 and 50 years with females (52%) outnumbering males (48%). The most common site was the face (38%), and the common morphology was plaque (60%). Sign of Leser-Trélat was observed in five patients of which three were associated with malignancy that includes two lymphomas and one breast carcinoma. The color on dermoscopy was predominant dark brown (43%) and brownish-black (32%). The common element was clod (39%) and combined clod and dots (18%). More than three colors and more than two elements in a single lesion were observed in 15 and 11% of cases, respectively. The dermoscopic clues of seborrheic keratosis with highest to lowest prevalence were cerebriform pattern (76%), sharp demarcation (64%), comedone-like opening (56%), milia-like cyst (54%), mica-like scales (52%), moth-eaten border (46%), jelly sign (40%), fingerprint-like pattern (40%), fat fingers (36%), peripheral globules/network (34%), coral-like structure (26%), papillary structures (26%), irregular globules (12%), irregular opaque brown pigmentation (12%), and yellow-orange areas (3%). The flat seborrheic keratosis predominantly showed an irregular network-like structure, fat fingers, milia-like cyst, and accentuation of two adjacent perifollicular pigmentations forming a double ring-like structure (16%). The raised lesions predominantly showed fissures/ridges (cerebriform pattern), exophytic papillary structures, opaque pigmentation, and a mica-like pattern. Ten lesions were misinterpreted as seborrheic keratosis clinically and on dermoscopy were verruca vulgaris (2/10, 20%), melanocytic nevus (3/10, 30%), and basal cell carcinoma (5/10, 50%), which were confirmed on histopathology. Conclusion The study emphasizes the use of dermoscopy in seborrheic keratosis to improve the clinical accuracy of diagnosis and also to differentiate from its common mimickers.

In-Built Fabrication of MOF Assimilated Porous Hollow Carbon from Pre-Hydrolysate for Supercapacitor.

With the fast consumption of traditional fossil fuels and the urgent requirement for a low-carbon economy and sustainable development, supercapacitors are gaining more and more attention as a clean energy storage and conversion device. The research on electrode materials for supercapacitors has become a hot topic nowadays. An electrode material for a supercapacitor, comprising the ZIF-67 in-built carbon-based material, was prepared from a biomass pre-hydrolysate via a hydrothermal process. As a by-product of dissolving slurry, the pre-hydrolysate is rich in carbon, which is an excellent biomass resource. The utilization of pre-hydrolysate to prepare carbon energy materials could realize the high value utilization of pre-hydrolysate and the efficient energy conversion of biomass. Meanwhile, the cobalt-based MOF (such as ZIF-67), as a porous crystalline material, has the advantages of having a regular order, high specific surface area and controllable pore size, as well as good thermal and chemical stability. The addition of ZIF-67 modified the morphology and pore structure of the carbon, and the obtained samples showed outstanding electrochemical performance. One- and two-step synthetic processes generated specimens with a coral-like cross-linked structure and a new type of rough, hollow, dandelion-like structure, respectively, and the pore size was in the range of 2.0–5.0 nm, which is conducive to ion transport and charge transfer. In C2-ZIF-67, the hollow structures could effectively prevent the accumulation of the electrochemical active center, which could provide enough space for the shrinkage and expansion of particles to protect them from the interference of electrolytes and the formation of solid electrolyte interphase film layers. Additionally, the plush tentacle structure with low density and a large specific surface area could expose more active sites and a large electrolyte electrode contact area, and short electron and charge transport paths. Importantly, active, free electrons of small amounts of Co-MOF (1 wt%) could be stored and released through the redox reaction, further improving the electrical conductivity of Carbon-ZIF-67 materials in this work. Consequently, C2-ZIF-67 exhibited superior specific capacitance (400 F g−1, at 0.5 A g−1) and stability (90%, after 10,000 cycles).

Facile synthesis of hierarchical porous two-dimensional N-doped carbon nanosheets as bi-functional electrode for superior supercapacitor and photo-catalyst

The hierarchical porous nitrogen-doped two-dimensional carbon (HNGC) was prepared by simple calcination of magnesium sulfate (MgSO4) and self-synthesized nitrogen-doped two-dimensional graphene-like carbon at a mild temperature in oxygen. The influence MgSO4 on the morphology, structure and chemical composition of the prepared HNGC samples were studied using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, surface area analysis, X-ray photoelectron microscopy and elemental analyzer. HNGC-2 exhibited a uniform three-dimensional coral-like porous inter-connected structure, large specific surface area, high pore volume, and no loss of nitrogen content. HNGC-2 demonstrated an excellent rate capability of 62.8% at 20 A g−1, outstanding stability of 96.1% following 5000 cycles and the assembled symmetric supercapcitor achieved 12.5 Wh kg−1 at a 350 Wkg-1 and 7.5 Wh kg−1 at 3500 Wkg-1. The novel method was also found to be effective for facilitating the electrochemical performance of commercial biomass active carbon. In addition, HNGC-2 was used for the photo-catalytic degradation of methylene blue and over 99% of methylene blue was successfully degraded under 25-min visible irradiation in the presence of potassium persulfate. The enhanced electrochemical performance and the excellent photo-catalytic performance of HNGC-2 indicated that porous carbon can be successfully activated using an appropriate oxidation strategy.

Peroxymonosulfate activation by iron self-doped sludge-derived biochar for degradation of perfluorooctanoic acid: A singlet oxygen-dominated nonradical pathway

The harmful effects on environment and human health caused by the widespread use of perfluorooctanoic acid (PFOA) have appealed much attention. However, traditional advanced oxidation processes (AOPs) are usually inefficient for PFOA degradation. In this study, iron species self-doped biochar derived from municipal sludge (ISBC) was synthesized by a simple method of EDTA-citric acid (CA) leaching/pyrolysis, exploring an efficient activation method of peroxymonosulfate (PMS) for PFOA degradation. Results showed that most of heavy metals were recovered from the sludge via the EDTA-CA pretreatment, at the same time, the special coral-like porous structure were formed in ISBC. A larger specific surface area and pore volume, as well as uniform Fe and N elements distribution of ISBC facilitated the reaction of surface PMS activation, which contributed to the enhancement in PFOA removal. Notably, it was found that pyridinic nitrogen and ketonic and quinone groups were key active sites, and their mediated singlet oxygen (1O2) was confirmed to be the dominated reactive species for PFOA removal in ISBC/PMS system, instead of the radicals mediated by iron species. Furthermore, a possible PFOA degradation pathway by the nonradical 1O2 oxidation was studied by combining density functional theory (DFT) calculation with experimental results. This study proposes a potential method to recover sludge heavy metals and activate PMS for PFOA and other organics simultaneously, which provides a valuable process for the water treatment and high value utilization of excess sludge.

Preparation of hollow nanosphere of 5-fluorouracil/layered double hydroxide and its cellular cytotoxicity

We have first prepared the layered double hydroxide (LDH)/carbon nanosphere (CNS) composite by mixing the LDH gel containing methoxide interlayer anion with the CNS template (particle size of 300–700 nm) suspension in methanol at room temperature under ultrasonication. The SEM observation indicates that the CNS core was uniformly covered with the LDH thin film made up by fine plate-like particles to form the composite. Then, the intercalation of anticancer drug, 5-fluorouracil (5-FU), into the LDH interlayer was carried out by the calcination-rehydration reaction and the solid products were analyzed using XRD, FT-IR, SEM, TEM etc. During the calcination process at 500 °C for 3 h, the CNS core was removed by combustion and the LDH shell became the hollow LDH oxide nanosphere. In the following rehydration process at 60 °C for 24 h, this oxide precursor was reconstructed the hollow LDH nanosphere having the surface of coral-like structure (spontaneously formed LDH particles) incorporating 5-FU anion in the interlayer. Finally, the anticancer drug efficacy in vitro of the products was estimated by using the WST-8 assays in HeLa cell lines. As the result, the hollow nanosphere of the 5-FU/LDH performed an improvement of drug efficacy compared to the conventional plate-like particle of the 5-FU/LDH as the reference and the naked 5-FU itself at the same 5-FU concentration.

Robust Dual-Biomimetic Titanium Dioxide-Cellulose Monolith for Enrichment of Phosphopeptides.

Metal oxide affinity chromatography (MOAC) is considered to be one of the most effective methods for phosphopeptide enrichment. However, most of the materials used in the method are powder; frequent centrifugation is necessitated during the enrichment process, and potential risks of loss of peptides and materials and clogging of the column employed for liquid chromatography-mass spectrometry (LC-MS) arise. Moreover, the reusability of these materials to achieve sustainability was hardly investigated. To overcome these limitations, herein, inorganic titanium dioxide (TiO2) was coated onto the skeletal surface of the organic cellulose monolith (CM) material with a coral-like structure via a sol-gel method. This produced an organic-inorganic hybrid TiO2-CM material, which contained a combination of organic and inorganic substances, making it mimic the mollusk shell in terms of composition. The prepared TiO2-CM material as monolith exhibited excellent mechanical strength and did not break during the enrichment process; thus, the tedious implementation of multiple centrifugation cycles was prevented, thereby streamlining the experimental procedure and avoiding the loss of peptides and materials. Moreover, a large amount of TiO2 was introduced onto the surface of the CM material, and thus, the resultant TiO2-CM material exhibited a large surface area. As a result, the fabricated TiO2-CM material was successfully applied to the enrichment of phosphopeptides obtained from the tryptic digests of a BSA/β-casein (mass ratio, 500/1) mixture. The results were superior to those achieved for commercial TiO2 beads, confirming that TiO2-CM has excellent selectivity for phosphopeptides and reusability. Furthermore, 9287 unique phosphopeptides derived from the 2661 phosphoproteins were successfully identified from two milligrams of tryptic digests of Hela cell exosomes obtained through five independent replications after enriching using the TiO2-CM material. The results indicated that the material has good application prospects in the analysis of protein phosphorylation. Furthermore, TiO2-CM consists of green and cheap cellulose as the skeleton, and its synthesis process is environment-friendly, simple, and inexpensive.

Coral-like carbon-based composite derived from layered structure Co-MOF-71 with outstanding impedance matching and tunable microwave absorption performance

• Porous coral-like carbon/Co 3 O 4 and carbon/Co materials were prepared for the first time through the calcination of precursor Co-MOF-71. • Pore structure and magnetic properties can be tuned by regulating the calcination temperature. • S500 achieves strong absorption and broad effective absorption under a thin coating thickness. Metal-organic frameworks (MOFs) are considered as a novel type of microwave absorption (MA) material owing to the sufficient pore structure, diverse configurations, and easy-to-control magnetic properties. However, their evolution is limited by the imperfect impedance matching conditions caused by the undesirable microstructure. Herein, two types of novel porous coral-like carbon/Co 3 O 4 and carbon/Co composites have been effectively fabricated for the first time by a facile heat treatment process of precursor Co-MOF-71. The graphitization degree, magnetic property and MA ability of the product can be effortlessly tuned by altering the heat treatment temperature of Co-MOF-71. Remarkably, S500 (Co-MOF-71 calcined at 500 °C) composite displays strong and multi-frequency absorption performance, whose minimum reflection loss (RL) value achieves -36.4 dB with an absorbing thickness of 3.0 mm and attains an effective absorbing bandwidth (RL≤-10 dB) of 5.76 GHz (almost covers whole Ku band) at a thinner coating thickness of 2.5 mm. Such superb MA ability has roots in the coral-like structure derived from the layer Co-MOF-71, sufficient electromagnetic loss. This work ameliorates the MA ability of MOFs through a special nanostructural design, which provides a fresh way for the preparation of novel MA materials.

Sponge-like carbon monoliths: Porosity control of 3D-printed carbon supports and its influence on the catalytic performance

Sponge-like carbon monoliths with tailored channel architecture and porosity were prepared by combining sol–gel polymerization and 3D printing technology. The pore size distribution (PSD) and macropore volume were controlled by varying the water concentration used in the synthesis. The size and interconnection degree of primary particles, and consequently the pore width and macropores volume, increases by increasing the water concentration. However, a more heterogeneous PSD was detected at high water concentration, due to the better-defined spheres-like morphology of primary particles which leaves voids and corners between fused spheres together with bigger macropores leaves by the coral-like structure. The role of this porosity control on the CuO/CeO2 catalytic performance was pointed out in the CO-PrOx reaction. The CuO/CeO2 dispersion and distribution along the carbon network increases by increasing the water concentration, i.e. the pore width and macropore volume, enhancing the catalytic activity. However, this improvement is not observed at high water concentration in which preferential flow pathways are created favored by the heterogeneous PSD. This manifest that the porosity control plays an important role in the catalytic performance of monolithic catalysts and thus, the monolithic support must be specifically designed to optimize the catalytic performance of active phases for each application.

Effect of the Anodizing Temperature on Microstructure and Tribological Properties of 6061 Aluminum Alloy Anodic Oxide Films

Anodizing a simple and effective method to improve the wear resistance of 6061 aluminum alloy. In this study, the microstructure of 6061 aluminum alloy oxide films (AAO) was adjusted by changing the electrolyte temperature (5, 15, and 25 °C) using 160 g/L sulfuric acid as the electrolyte. The phase composition, microstructure, and morphological characteristics of the specimens were detected using X-ray diffractometer and field emission scanning electron microscopy (SEM). The hardness, elastic modulus, and tribological properties of the films were examined using hardness testers and a rotary friction tester. The results showed that as the temperature of the electrolyte increases, the surface of the oxide films changes from uniformly distributed small-sized pores to a coral-like loose porous structure, and the thickness of the films increases. The electrolyte temperature has a significant effect on the friction performance of the AAO films. When the solution temperature decreases from 25 to 5 °C, the steady-state friction coefficient decreases from 0.46 to 0.39. According to the morphology of the wear tracks, it can be determined that the main wear mechanism of AAO films gradually changes from delamination wear to abrasive and adhesive wear, and the wear rate drops by ~69%.

Construction of highly hydrophobic and fast endothermic surfaces using candle soot and nano-TiO2

Abstract This work combines hydrophobic and heat-absorbing materials to solve the problem of water and frost resistance in industrial and domestic scenarios in harsh environments. Here, highly hydrophobic and fast endothermic (HHFE) surfaces were prepared by applying candle soot (nanocarbon) as the template, slides as the carrier and nano-TiO2 as a backbone and a connecting layer. The resulting HHFE surface exhibited a coral-like porous structure, which is beneficial to hydrophobic performance. The contact angle between the water droplet and the glass with the HHFE coating was about 120°, thus implying that the prepared HHFE surface with a TiO2 skeleton layer has excellent hydrophobicity. The hydrophobic mechanism of the HHFE surface can be explained by the Cassie–Baxter model. Infrared thermography and thermometry were used to record the thermal capacity and heat-absorbing rate of the HHFE surface. The temperature of the glass covered with the HHFE coating rose from 16°C to 38°C within 5 minutes, which is 46.2% higher in capacity and 2.2 times faster in rate than ordinary glass under the same solar irradiation. The resulting HHFE thin film consists of nanocarbon materials, and nano-TiO2 particles were hydrophobic and good heat absorbers. They have great potential for anti-freezing and water-proofing applications, especially in harsh environments.

Fabrication of high specific surface area TiO2 nanopowders by anodization of porous titanium

The specific surface area of TiO2 powders is an important factor affecting the performance. In this study, we present a simple and novel method to fabricate TiO2 nanopowders based on electrochemical anodization. TiO2 nanopowders with coral-like structure surface and maximum specific surface area of 280 m2/g were fabricated in an aqueous electrolyte containing 1 M Na2SO4 and 0.5 wt% NaF under applied potential of 10 V. Porous titanium as an anodic substrate enhances the reaction rate and promotes the shedding of nanotube fragments. The reaction yield of powders prepared at high-frequency 10 V is nearly 3.7 times higher than that prepared at constant potential 10 V. The specific surface area of the powder prepared at high-frequency-15 V is 61% higher than that prepared at constant potential 15 V.

Controllable Electrodeposition Adjusts the Electrochromic Properties of Co and Mo Co-Modified WO3 Films

Metal ion modification is considered to be an effective way to construct metal oxides with specific physical and chemical properties. In this paper, we prepare a tungsten oxide (WO3) film co-modified by Co-ion and Mo-ion to serve as the electrochromic material through a one-step electrodeposition method. The effect of electrodeposition time on film thickness, surface morphology and electrochromic properties is systematically studied as well. The results show that, compared with pure WO3 film, the surface morphology of the tungsten oxide film modified by Co-ion and Mo-ion (WO3: Co, Mo) is significantly different. The Co and Mo co-modified film possesses a higher transmission modulation (58.5% at 600 nm) and rapid switching speed (coloring and bleaching time are 2.7 s and 5.6 s, respectively), low impedance value and excellent cycle stability. The performance enhancement is mainly attributed to the coral-like structure of the membrane, which provides a larger specific surface area, more ion adsorption sites and faster ion diffusion. Therefore, this work provides a fast and low-cost method to prepare tungsten oxide electrochromic films co-modified with cobalt and molybdenum ions. At the same time, it also provides an idea to obtain films with different electrochromic properties by adjusting the film thickness.

One-Pot Thermal Synthesis of g-C3N4/ZnO Composites for the Degradation of 5-Fluoruracil Cytostatic Drug under UV-LED Irradiation.

Graphitic carbon nitride (g-C3N4) was used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of 5-fluorouracil (5-FU) cytostatic drug under UV-LED irradiation. CN/ZnO composites were synthetized by an easy one-pot thermal method, varying the g-C3N4 loading, i.e., from 10 to 67 wt% and a post-thermal exfoliation in air. The physicochemical and optical properties of the materials were analyzed by several techniques. CN/ZnO composites showed a coral-like structure of spherical ZnO wurtzite particles on the g-C3N4 structure. In general, the synergism and heterojunction interface between both phases allowed the enhancement of the mesoporosity, light absorption ability, and the aromaticity of the corresponding composites. Moreover, the photocatalytic activity of the CN/ZnO composites was increased with the addition of g-C3N4 in comparison with pristine ZnO. The highest activity was found for the composite containing 25 wt% of g-C3N4 (i.e., CN25/ZnO), reaching the total degradation of 5-FU and a mineralization of 48% at 180 min, as well as a good photostability during four reuse cycles. Experiments with different pH solutions and scavengers allowed for the assessment of the reactive oxygen species (ROS) involved in the 5-FU degradation pathway, with radicals and non-radical species as the main responsible active species. Furthermore, a tentative photocatalytic mechanism was proposed for CN/ZnO composites.

Polyimide-derived porous carbon/Co particle-based composites for high-performance microwave absorption.

A simple method that combines liquid-liquid phase separation and high-temperature pyrolysis has been developed for the synthesis of polyimide-derived porous carbon/Co particle-based composite absorbers (PIC/Co-800 and PIC/Co-1000). The excellent heat resistance of polyimide allows the composite precursor to maintain its porous structure during pyrolysis. According to the results, PIC/Co-800 and PIC/Co-1000 have a coral-like porous structure, which can enhance the impedance matching property and microwave attenuation ability of the synthesized materials. The impedance matching condition and dissipation ability of PIC/Co-800 and PIC/Co-1000 have been enhanced due to the synergistic effect between the carbon-induced dielectric loss and Co nanoparticle-induced magnetic loss. PIC/Co-1000 shows the highest absorption performance with a minimum reflection loss (RL) of -40.22 dB at a thickness of 5.3 mm and an effective absorption bandwidth (EABW, RL ≤ -10 dB) of 4.10 GHz at a thickness of 1.4 mm. With thicknesses in the range of 1.4 mm to 5.3 mm, the minimum RL value of each thickness is lower than -15 dB. Therefore, this work provides a new strategy for the synthesis of promising absorbing materials with outstanding EMW absorption performance.

Fabrication of a durable coral-like superhydrophilic MgO coating on stainless steel mesh for efficient oil/water separation

A superhydrophilic/underwater superoleophobic MgO&SSM coating on SSM (stainless steel mesh) with micro-nano coral-like structure was fabricated by high-temperature treatment of SSM soaked with magnesium nitrate solution. This unique coral-like structure gives it a super high specific surface area and a large number of hydroxyl groups are exposed to the surface. The oil–water separation efficiency achieved 99.0% and the flux attained to 6195 L·m−2 h−1. And the oil–water separation efficiency was always as high as 98.0% after 10 times of repeated use. In addition, it could still maintain underwater superoleophobicity after immersing them in different pH solutions (pH, 5–12) or saturated NaCl solutions for a certain period of time. More importantly, it still maintained underwater superoleophobicity and shown excellent weather resistance after being treated at different temperatures for 2 h or after being exposed to ultraviolet rays at elevated temperatures for 6 h.

Ultralight Coral-like hierarchical Fe/CNTs/Porous carbon composite derived from biomass with tunable microwave absorption performance

In order to widen the application field of microwave absorption (MA) materials, it is still challenging to obtain high-performance MA materials with wide frequency bandwidth, lightweight, thin thickness, and strong absorption by an economical and sustainable method. Herein, the novel coral-like hierarchical structure with zero-dimensional Fe nanocrystals, one-dimensional N-doped carbon nanotubes (CNTs) and three-dimensional porous carbon (PC) matrix is rationally constructed to enhance MA performance. Based on renewable biomass residues, the composite consisted of PC as matrix, bamboo-shaped CNTs with magnetic nanoparticles at the top grow on the surface of PC. By controlling the growth conditions of carbon nanotube, the microstructure and dielectric loss capacity of composite can be manipulated to optimize the impedance matching, reflection loss (RL), and effective absorption bandwidth (EAB, the bandwidth of RL < -10 dB). Benefitting from the unique architecture and hierarchical composite, the composite exhibited a minimum RL of −70 dB at thin thickness of 1.9 mm under low filler content of 12.5 wt%. Even with the thickness of 1.5 mm, the RL could reach −51.8 dB with a broadcast EBA of 5.0 GHz. This work provides an insight for designing advanced microwave absorbers with lightweight, thin thickness, strong RL, and wide EAB.