Changes In Surface Morphology Research Articles

Pool-boiling enhancement on periodic micro/nano ripple-structured surfaces fabricated by femtosecond laser

A study was conducted on whether periodic micro/nano ripple structures generated on metal surfaces using femtosecond laser processing could improve pool boiling heat transfer. Depending on the laser irradiation conditions on the metal surface, a surface structure with different geometrical characteristics is created. Changes in sample surface morphology caused by the laser irradiation intensity are examined using scanning electron microscopy and confocal laser microscopy. Pool boiling tests are conducted to compare three laser irradiation conditions fabricated samples and the bare copper surface. The working fluid is deionized water. The pool boiling curves of each sample surface were compared with each other. Visualization of bubble nucleation is performed using a high-speed camera. The superheat, bubble departure diameter, and bubble growth period of each sample are measured and compared at the onset of nucleate boiling (ONB). The most efficient periodic micro/nano ripple-structured surface reduces the superheat at the ONB by 6.13 °C in comparison with that at the bare Cu surface. The enhanced surface structure reduced the bubble departure diameter and renewal period by 60.5% and 55.6% in comparison with that of the smooth surface. Further, the structured surface showed 178.5% enhancement in heat transfer coefficient and 39.1% in critical heat flux, respectively. Thus, the combination of increased nucleate site density, high nucleation site activation, and a wicking effect in the periodic micro/nano ripple structure significantly improves the pool boiling heat transfer.

Differential cytotoxicity to human cells in vitro of tire wear particles emitted from typical road friction patterns: The dominant role of environmental persistent free radicals

Tire wear particles (TWPs) have been recognized as one of the major sources of microplastics (MPs), however, effects of initial properties and photochemical behavior of TWPs on cytotoxicity to human cells in vitro have not been reported. Therefore, here, three TWPs generated from typical wear of tires and pavements (i.e., rolling friction (R-TWPs) and sliding friction (S-TWPs)) and cryogenically milled tire tread (C-TWPs), respectively, and their photoaging counterparts were used to study the reasons for their differential cytotoxicity to 16HBE cells in vitro. Results showed in addition to changes of surface structure and morphology, different preparation methods could also induce formation of different concentration levels of environmental persistent free radicals (EPFRs) (from 1.24 to 3.06 × 1017 spins/g with g-factors ranging 2.00307–2.00310) on surfaces of TWPs, which contained 7.3%–65.8% of reactive EPFRs (r-EPFRs). Meanwhile, photoaging for 90 d could strengthen formation of EPFRs (from 4.03 to 4.61 × 1017 spins/g) with containing 74.7%–78.1% r-EPFRs on surfaces of TWPs and improve their g-factor indexes (ranging 2.00309–2.00313). At 100 μg mL−1 level, compared to C-TWPs, both R-TWPs and S-TWPs (whether photoaging or not) carried higher intensity EPFRs could significantly inhibit 16HBE cells proliferation activity, cause more cells oxidative stress and induce more cell apoptosis/necrosis and secretion of inflammatory factor (P < 0.05). However, regardless of how TWPs were prepared, photoaged or not, exposure at a concentration of 1 μg mL−1 appeared to be non-acute cytotoxic. Correlation analysis suggested dominant toxicity of TWPs was attributed to the formation of r-EPFRs on their surfaces, which could promote accumulation of excess reactive oxygen species in cells and the massive deposition of intracellular particles. This study provides direct evidence of TWPs cytotoxicity, and underlining the need for a better understanding of the influences of initial properties and photochemical characteristics on risk assessment of TWPs released into the environment.

Preparation and properties of nitride multilayer coating modified stainless steel as bipolar plates for proton exchange membrane fuel cells

Nitride multilayer coating is prepared on 316L stainless steel (SS) by employing multi-arc ion planting to enhance the corrosion resistance, interfacial electrical conductivity, and hydrophobicity. The electrochemical results show that the coating can effectively inhibit the interface reactions. The icorr of the coated 316L SS was 0.04 μA cm−2, which was significantly lower than that of the substrate (54.7 μA cm−2). The protection efficiency (Pi) of the multilayer nitride coating was 99.93%. After 9 hours of PP, the current density of the coated 316L SS stabilized at 0.085 μA cm−2. The typical ICR value of the coated 316L SS slightly increased from 8.6 mΩ cm2 to 12.6 mΩ cm2. The XPS results demonstrated that the significantly increased ICRs (114.7–200.4 mΩ cm2) of the 316L SS substrate were mainly attributed to the increased proportion of Cr oxide, while the oxide content of the coating was still relatively small. The change in surface morphology and current transient events are further discussed.

Use of Co3O4 nanoparticles with different surface morphologies for removal of toxic substances and investigation of antimicrobial activities via in vivo studies.

Co3O4 nanoparticles (NPs) were formed using hydrothermal synthesis method and various surfactants to study the effect of changing surface morphology on catalytic and antibacterial activities. FT-IR, TEM, SEM, BET, XRD, and XPS analyses were performed to characterize the NPs. It was observed that as the morphology of Co3O4 changes, it creates differences in the reduction efficiency of organic dyes and p-nitrophenol (p-NP), which are toxic to living organisms and widely used in industry. The reaction rate constants (Kapp) for Co3O4-urea, Co3O4-ed, and Co3O4-NaOH in the reduction of p-NP were found to be 1.86 × 10-2s-1, 1.83 × 10-2s-1, and 2.4 × 10-3s-1, respectively. In the presence of Co3O4-urea catalyst from the prepared nanoparticles, 99.29% conversion to p-aminophenol (p-AP) was observed, while in the presence of the same catalyst, 98.06% of methylene blue (MB) was removed within 1h. The antibacterial activity of Co3O4 particles was compared with five standard antibiotics for both gram-positive and gram-negative bacteria. The results obtained indicate that the antimicrobial activity of the synthesized Co3O4 particles has a remarkable inhibitory effect on the growth of various pathogenic microorganisms. The current work could be an innovative and beneficial search for both biomedical and wastewater treatment applications.

Microcosmic mechanism of metal–organic framework enhanced thermoplastic polyurethane exposed to laser-induced shock wave

Incorporating nano-particles into polymer matrix has enabled improving shock wave mitigation (SWM) ability. Vast majority of researchers adopted inorganic nano-materials to enhance polymer matrix. Due to the incompatibility between inorganic nano-particles and polymers, complicated interface modification processes were often used. Metal–organic frameworks (MOFs) have good compatibility with polymers and show excellent SWM capabilities. However, they are brittle and experience lattice collapse after shock loading. Based on this, thermoplastic polyurethane (TPU) enhanced by zeolitic imidazolate framework-8 (ZIF-8) was proposed and prepared. The mixtures can not only improve the SWM ability of polymers, but also address the brittleness of MOFs. Additionally, scholars often use simulation methods to study energy dissipation mechanism of materials, rarely evidences of microstructural changes observed to support theoretical speculations. In this work, by analyzing surface morphology and molecular structural changes, energy dissipative mechanism was investigated. With addition amount of 5 wt% and 10 wt% ZIF-8 particles in TPU, the pressure can be reduced by 0.074 GPa and 0.1478 GPa than neat TPU. TPUM-10 had a stronger deformation resistance and SWM ability. Moreover, main chemical structures were remained unchanged after shock. The increased ability of SWM may relate to hydrogen bond forming process and delayed material failure.

Influence of Polyethylenimine (PEI) in enhancement of microstructure and surface morphology of recycled construction and demolition waste aggregate in concrete by carbonation

This investigation explores the influence of Polyethylenimine (PEI) on the improvement of carbon dioxide (CO2) uptake, surface texture, and pore structure of construction and demolition waste (CDW) through carbonation. The study focuses on the coarser fraction of CDW (10 mm), which is pre-treated with varying concentrations of PEI before being carbonated. The resulting changes in pore structure, mineralogical composition, physical properties, and surface morphologies of the CDW are characterized using various techniques. The study also evaluates the impact of carbonated CDW on compressive strength. The results indicate that PEI modification of CDW enhances carbonation efficiency by reducing pores more effectively than non-treated CDW. This microstructural refinement is possible due to the formation of calcite and its products, facilitated by PEI adsorption into CDW, enhanced CO2 uptake, and formation of calcite products through carbonation. Additionally, PEI modification results in the formation of undulated plate-like structures that enhance surface morphology and compressive strength when used in concrete. The carbonation behavior of PEI-modified CDW in concrete was also investigated by analyzing carbonation depth and pH value. The results reveal that the optimal PEI concentration for enhancing the performance of CDW is 0.2. Overall, the study highlights the potential of PEI modification as an effective approach to improve the properties of CDW and its potential as a sustainable construction material.

Calcination and ion substitution improve physicochemical and biological properties of nanohydroxyapatite for bone tissue engineering applications

Nanohydroxyapatite (nanoHAP) is widely used in bone regeneration, but there is a need to enhance its properties to provide stimuli for cell commitment and osteoconduction. This study examines the effect of calcination at 1200 °C on the physicochemical and biological properties of nanoHAP doped with magnesium (Mg2+), strontium (Sr2+), and zinc (Zn2+). A synergistic effect of dual modification on nanoHAP biological properties was investigated. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET analysis, Fourier-transform spectroscopy, and thermal analysis methods. Furthermore, ion release tests and in vitro biological characterization, including cytocompatibility, reactive oxygen species production, osteoconductive potential and cell proliferation, were performed. The XRD results indicate that the ion substitution of nanoHAP has no effect on the apatite structure, and after calcination, β-tricalcium phosphate (β-TCP) is formed as an additional phase. SEM analysis showed that calcination induces the agglomeration of particles and changes in surface morphology. A decrease in the specific surface area and in the ion release rate was observed. Combining calcination and nanoHAP ion modification is beneficial for cell proliferation and osteoblast response and provide additional stimuli for cell commitment in bone regeneration.

Testing of a new ionizing radiation detector based on multimode optical fibers

"This paper presents our results investigation to evaluation effects of the electron beams radiation generated in multimode optical fibers at high irradiation doses in order to develop an ionizing radiation dosimeter. The radiation induced attenuation has been shown to exhibit a linear dependence as a function on the applied dose on a certain doses range and after the irradiation the optical fibers go through a “recovery process” during which the optical properties improve again. The surface morphological changes due to electron beam irradiation were investigated by Scanning Electron Microscopy and Atomic Force Microscopy."

Exploring particle-current collector contact damage in Li-ion battery using DEM-FEM scheme

Calendering is an essential step in the manufacturing process of lithium-ion batteries. However, the intrusion of active particles into metal foil can damage the current collector during calendering. Here, we investigate the changes in surface morphology and the tensile properties of current collector after calendering. The damage mechanisms of tensile strength reduction for current collector due to compressive pressure are revealed by combining the calendering tests, tensile experiments, and simulations. Specifically, the DEM-FEM scheme is proposed, which combines the discrete element method (DEM) with the finite element method (FEM) to characterize the mechanical behavior of current collectors after the intrusion of active particles. The results show that the current collectors become more brittle and vulnerable with the increase of compressive pressure. Finally, the failure phase diagrams are presented during the winding and electrochemical processes. This study can reveal the failure behavior of current collectors and guides the electrode manufacturing optimization.

Degradation of poly-L-lactic acid biopolymer films in Ca(OH)2-dosed fresh human urine collected in source-separating sanitation systems

Alkaline dehydration is a promising technology for producing organo-mineral fertiliser from source-separated human urine, but potential risks to users from handling alkaline earth hydroxides at source and carbonation of hydroxides during dehydration limit its implementation in real-life settings. These issues could be addressed by enclosing chemicals in bio-derived polymers. In this study, we investigated degradation and erosion of poly-L-lactic acid (PLLA) biopolymer films of different thicknesses (0.05, 0.1 and 0.25 mm) in Ca(OH)2-dosed fresh urine and Milli-Q water at two temperatures (20 °C and 45 °C). Evaluation of degraded films by XRD, GPC and SEM showed changes in crystallinity, reduction in molecular weights and change in surface morphology, respectively. SEM/EDX, FTIR and ICP-OES data indicated that L-CaL2, L-lactides and lactic acid were formed in urine. Overall, we found that thinner films, higher temperature and higher pH accelerated PLLA degradation in urine.

Bentonite-Clay/CNT-Based Nano Adsorbent for Textile Wastewater Treatment: Optimization of Process Parameters

Dyes are the most carcinogenic organic compounds that are discarded by most of the textile industries without any prior treatment, which is harmful for the environment. This study aims to develop a bentonite-clay/carbon-nanotube (CNT)-based adsorbent to treat textile wastewater for water sustainability. The preliminary and post-characterization of adsorbent involves scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) and energy-dispersive X-ray (EDX) analysis to determine the changes in surface morphology, functional group, and surface area of the adsorbent. Linear and nonlinear isotherms and kinetic studies were performed to explore the sorption mechanism. The results show that the nonlinear form of the Langmuir isotherm best fits adsorption with a qmax of 550 mg/g. The adsorption followed the nonlinear pseudo-first-order kinetics, favoring chemisorption with R2 ≈ 1 and X2 = 0.22. Maximum dye removal (89.9%) was achieved under the optimum conditions of pH 3, an adsorbent dose of 100 mg, and a contact time of 120 min, with an initial COD concentration of 1140 mgL−1. This study has demonstrated the successful application of a bentonite-clay/CNT-based adsorbent on textile wastewater treatment.

Removal of copper contamination from simulated wastewater using chitosan and shrimp waste: Equilibrium analysis

This study addressed copper removal from aqueous solution using unprocessed shrimp tail shell waste (STW) with comparison to removal by chitosan derived from shrimp shell. The use of a copper ion selective electrode enabled continuous copper concentration measurement and determination of the STW mass-time relationship needed to achieve the USEPA Maximum Contaminant Level for copper as a function of adsorbent dose. Copper removal using chitosan produced a blue solid without surface morphology changes, consistent with an adsorption or ion exchange mechanism. Calcium carbonate in the STW was essential for copper removal by the formation of a green copper-containing deposit primarily on the exposed edges of the ground shrimp solids and an increase in calcium concentration and pH in the treated solution. The systems reached equilibrium over several days. Equilibrium data were fitted to the Freundlich, Langmuir, Temkin, Sips, and B-E-T isotherms and the Freundlich model fit the data well. Raw STW, cooked STW, and chitosan with particle sizes ranging from 425 to 850 µm gave a maximum copper loading of 184 mg/g, 170 mg/g, and 129 mg/g, respectively. Both raw and cooked STW had higher copper capacities than commercial chitosan and provide a low cost and environmentally friendly adsorbent. Comparison of small particle size (< 425 µm) adsorbents after six hours showed that raw STW had double the copper loading of chitosan. Small STW achieved greater than 97.4% copper removal from a 50 mg/L copper solution and reached the MCL in less than one hour for 1.5 g/L loadings.

Corrosion processes at the GGG40 steel–bentonite interface

Abstract. Spheroidal graphite cast iron (GGG40/0.7040) is used as an overpack material for the reference Pollux 10 container, a prototype for the storage of fuel elements in different types of host rocks (Hassel et al., 2019). Corrosion processes are expected to be triggered after some decades, as the contacting bentonite, which is used as fill material, becomes soggy because of the decay of the fission heat generation and the intrusion of pore water as the temperature decreases under the condensation point (King and Padovani, 2011). The distinct electrochemical reactivities of the graphite, ferrite, pearlite, and cementite phases exposed by this material introduce local galvanic elements which influence the topographic evolution of degradation (Spence, 2005). The aim of this work is to elucidate the corrosion dynamics of active and passive areas by following the chemical evolution at the interface of cast iron–bentonite during the first stages after its saturation with geological pore water. Polarization experiments and electrochemical impedance spectroscopy were applied to monitor the corrosion process in a bentonite cell, where GGG40 steel is put into contact with a light compacted Wyoming bentonite slurry 1 : 10 w/w of bentonite to Opalinus Clay pore water (Fig. 1a). Experiments were performed at 30 and 50 ∘C for longer than 3 months. The surface chemistry and morphological changes were investigated by local XPS, SEM-EDX, and TEM (X-ray photoelectron spectroscopy, scanning electron microscopy with energy dispersive X-ray, and transmission electron microscopy, respectively). These experiments were complemented with corrosion studies performed in pore water under different temperatures, hydrostatic pressures, and pH and with and without dissolved oxygen. The polarization curves indicate a constant corrosion rate of GGG40 steel in saturated bentonite after 30 d. SEM micrographs reveal a preferential dissolution of the ferrite phase around the graphite spheres and the ferrite lamellae contained in the pearlitic eutectic. A strong localized dissolution of ferrite along the graphite boundary can be also observed; this is a typical case of crevice corrosion caused by the unhindered access of oxygen to the graphitic cathodic areas (Wang et al., 2022). The surface chemical studies indicate the accumulation of iron oxides, which can be attributed to a hydrated magnetite and the formation of iron silicates (Zhang et al., 2021). TEM pictures of a cross-sectional lamella, including part of graphite sphere, show the formation of a silicate film covering the corroding surface with an irregular adherence (Fig. 1b). The initial relatively high corrosion rate of GGG40 steel can be attributed to the dissolution of the more active ferrite with the formation of poorly passivating iron oxides and silicates. The system is driven towards the dissolution of pearlite at more positive electrode potentials. The bentonite slurry limits the access of oxygen to the graphitic cathodic areas, reducing the corrosion rate by 1 order of magnitude in comparison with that in aerated pore water. A surface enrichment of cementite with superior passive properties and the neutralization of the local elements by approaching the corrosion potential of graphite (Kadowaki et al., 2019) is also expected. Thus, the consumption of oxygen and the transport limitation of the cathodic reaction by bentonite forecast a considerable reduction in the degradation of the container after a sacrificial corrosion phase.

Nanosynthesis and Characterization of Cu1.8Se0.6S0.4 as a Potential Cathode for Magnesium Battery Applications.

Copper selenide (Cu-Se) and copper sulfide (Cu-S) are promising cathodes for magnesium-ion batteries. However, the low electronic conductivity of Cu-Se system results in a poor rate capability and unsatisfactory cycling performance. Mg-ion batteries based on the Cu-S cathode exhibited large kinetic barriers during the recharging process owing to the presence of polysulfide species. This work attempts to circumvent this dilemma by doping Cu1.8Se by sulfur, which replaces the selenium in the CuSe lattice to form Cu1.8Se0.6S0.4 nanocrystalline powder. The presence of sulfur will increase the electronic conductivity, and the presence of selenium will mitigate the effect of polysulfide species that hinder the kinetics of Mg2+. Herein, a Cu1.8Se0.6S0.4 nanocrystalline powder was synthesized by the solid-state reaction, yielding a highly pure and stoichiometric powder. The crystallographic structure of the nanopowder and the conversion-type storage mechanism have been attested via ex situ X-ray diffraction and energy-dispersive X-ray analysis. The nanocrystalline feature of Cu1.8Se0.6S0.4 was demonstrated by high-resolution transmission electron microscopy. An apparent surface morphology change during the charging/discharging process has been visualized by a field emission scanning electron microscope. Diffuse reflectance spectroscopy has discussed the variation of the band gap during charging and discharging. The full Mg/Cu1.8Se0.6S0.4 cells presented an initial discharge capacity of 387.99 mAh g-1 at a current density of 0.02 mA cm-2; moreover, they show moderate diffusion kinetics with ≈ 10-15 cm-2 s-1.

Enhanced ammonia gas sensing by cost-effective SnO2 gas sensor: Influence of effective Mo doping

Metal oxide based semiconductors play a vital role in the development of cost-effective gas sensors. In this study, undoped and Mo-doped SnO2 films were deposited using nebulizer spray by varying Mo doping concentrations from 0 to 1.5 wt% (in steps of 0.5 wt%) at the substrate temperature of 350°C. Ammonia vapour was used as the test gas. The effect of Mo doping concentration on the gas sensing ability of SnO2 films was investigated. Among the tested samples, the SnO2: Mo film with 1 wt% of Mo doping exhibits the best response (21 s) and recovery (31 s) times. The XRD results revealed the tetragonal structure and a decrease in the crystallite size upon doping. The Mo doping caused noticable changes in oxygen vacancies (as observed from PL), surface morphology, grain size and surface roughness which are found to be favourable for effective gas sensing.

Surface appearance and morphology changes of Asian lacquer due to artificial aging: Impacts of traditional additives

Asian lacquer is one of the earliest natural polymers used in human history. Objects made with decorative Asian lacquer are among the most exquisite collections in museums. This is the first systematic study on the influence of historically used additives on the appearance and morphology changes of unaged and aged lacquer coatings. Macro and microanalytical methods were optimized to investigate the surface changes of lacquer caused by artificial aging. These included visual observation, visible photography, optical measurements (gloss, haze, blanching, macro-texture and color) and microscopy. Results showed that additives altered the transparency, color, and surface roughness and waviness of unaged lacquer surfaces. Aging caused changes in surface morphology, particularly an increase in roughness due to cracking and pitting, and waviness. The transparency of transparent coatings also increased with aging. The widest cracks and earliest formation of cracks with aging were observed for thitsi mixed with wood oil. High surface roughness was observed for aged lacquers treated with iron and for vermillion formulations. A significant reduction in gloss and an increase in blanching was observed for aged iron-treated lacquers due to extensive pitting and cracking. Formulations with vermillion exhibited the largest surface pits, which led to the largest reduction in gloss and the most blanching. Aging caused black spots and darkening of the vermillion pigment. Aged formulations with carbon black exhibited large pits on the surfaces. Analyses of the cracking showed that, to a large extent, the width, length and number of cracks were influenced by components in the formulations. The phenomena of crack closure and displacement were identified for the first time in lacquered objects. The causes of blanching are discussed and the extent of blanching was tentatively quantitatively expressed by gloss and haze data obtained by a goniophotometer. In general, changes in appearance and morphology occurred from the beginning of the light aging cycle, except for cracking. Preventive conservation strategies during exhibition and storage should be tailored according to the formulation and preservation conditions of specific lacquer coatings. This study contributes to the knowledge and conservation of Asian lacquered surfaces. The analytical protocols may also be of value for studying and documenting other coating formulations, and the surfaces of works of art.

Thickness, Annealing, and Surface Roughness Effect on Magnetic and Significant Properties of Co40Fe40B10Dy10 Thin Films.

In this study, Co40Fe40B10Dy10 thin films were deposited using a direct current (DC) magnetron sputtering technique. The films were deposited on glass substrates with thicknesses of 10, 20, 30, 40, and 50 nm, and heat-treated in a vacuum annealing furnace at 100, 200, and 300 °C. Various instruments were used to examine and analyze the effects of roughness on the magnetic, adhesive, and mechanical properties. From the low frequency alternating current magnetic susceptibility (χac) results, the optimum resonance frequency is 50 Hz, and the maximum χac value tends to increase with the increase in the thicknesses and annealing temperatures. The maximum χac value is 0.18 at a film thickness of 50 nm and an annealing temperature of 300 °C. From the four-point probe, it is found that the resistivity and sheet resistance values decrease with the increase in film deposition thicknesses and higher annealing temperatures. From the magnetic force microscopy (MFM), the stripe-like magnetic domain distribution is more obvious with the increase in annealing temperature. According to the contact angle data, at the same annealing temperature, the contact angle decreases as the thickness increases due to changes in surface morphology. The maximal surface energy value at 300 °C is 34.71 mJ/mm2. The transmittance decreases with increasing film thickness, while the absorption intensity is inversely proportional to the transmittance, implying that the thickness effect suppresses the photon signal. Smoother roughness has less domain pinning, more carrier conductivity, and less light scattering, resulting in superior magnetic, electrical, adhesive, and optical performance.

The role of ZnO nanowires to improve methanol selectivity on Cu2O nanocubes during CO2 electroreduction

Electrochemical reduction of CO2 enables a flexible and efficient way of converting CO2 into diverse products. Cu2O is regarded as a crucial species for electrocatalytically transforming CO2 to methanol while facing challenges such as the deactivation of the catalyst and low selectivity of desired products. Therefore, the modification of Cu2O and the improvement of its catalytic activity needs to be addressed. Herein, we reported a novel synthesis of Cu2O nanocubes (Cu2O-cube) using the wet chemical method and demonstrated a Faradaic efficiency of 29.1 % for methanol. We found Cu2O (100) facet was responsible and beneficial to improve methanol production. The performance degradation at different potentials due to the deactivation of Cu2O-cube were revealed from the changes of surface morphologies by scanning electron microscope (SEM). The electrocatalytic activity of Cu2O-cube was further enhanced by embedding Cu2O-cube into ZnO nanowires (ZnO@Cu2O-cube) through drop-drying, leading to a Faradaic efficiency of 38.9 % towards methanol at − 0.45 V vs. RHE. For parallel comparison, an alternative binding form of ZnO and Cu2O was investigated through stacking Cu2O film onto ZnO nanowires (ZnO@Cu2O-film) through electrodeposition. The results elucidated that the existence of ZnO tended to suppress the production of ethanol and the binding site of ZnO-Cu2O could improve the selectivity of methanol.

Improving the Performance of Poly(caprolactone)-Cellulose Acetate-Tannic Acid Tubular Scaffolds by Mussel-Inspired Coating.

Small-diameter artificial blood vessels are increasingly being used in clinical practice. However, these vessels are prone to thrombus, and it is necessary to improve blood compatibility. Surface coating is one of the commonly used methods in this regard. Inspired by the biomimicry of mussels, the use of deposition technology to obtain coating coverage on the surface of fibers has significantly piqued the interest of researchers recently. In this study, tubular scaffolds consisting of a composite of poly(caprolactone), cellulose acetate, and tannic acid (TA) were electrospun, and then the scaffolds were treated with different Fe(III) solutions (iron(III) chloride hexahydrate (FeCl3'6H2O)) to obtain four tubular scaffolds: F0, F5, F15, and F45. According to scanning electron microscopy (SEM) and field emission-SEM results, TA/Fe(III) complex is coated on the fiber of the scaffold after post-treatment; the fiber surface morphology changes with different Fe(III) concentrations. This provides designability to the performance of tubular scaffolds. The tensile strength of the F5 tubular scaffold (3.33 MPa) is higher than that of F45 (3.14 MPa), while the strain (83.9%) of the F45 tubular stent was 2.26 times that of the F5 (37.2%). In addition, cytotoxicity and antithrombotic performance were evaluated. The test results show that surface TA/Fe(III) coating treatment can affect the cytotoxicity and anticoagulation performance of the scaffold surface. The biomimetic TA/Fe(III) coating of mussels used in this study improves the performance of artificial blood vessels.

Li Electrodeposition Modeling for Analyzing the Effect of Li+ Redistribution in Li Metal Secondary Batteries

To meet the high-energy-density requirement of Li secondary batteries for EV applications, Li metal is still being re-examined extensively beyond conventional carbon-based anode active materials. However, unlike intercalation mechanism-based anodes, Li metal anodes (LMAs), suffering from significant surface morphology changes during electroplating and stripping, can accompany several issues such as Li dendrite growth and continuous side reactions, thereby leading to the poor electrochemical performance and cycle stability. Among various reasons of the Li dendrite formation, inhomogeneous and slow Li+ transport to the LMAs are representatively known, accelerating irregular electrodeposition and rapid Li+ depletion on the LMA surface.In this study, we attempted to simulate Li dendrite growth under practical current conditions by developing a 2D Li electrodeposition model. Based on this model, we analyzed the geometric-electrochemical characteristics of Li metal interface depending on Li+ concentration distribution in the electrolyte and SEI. Furthermore, in order to verify a nanomaterial-based micro-convection effect in the electrolyte for improving mass transfer, the Li+ concentration change nearby the interface was calculated while simulating the Li dendritic growth. Also, real 2D morphologies of the Li dendrites were reconstructed and analyzed together in a similar way. As a result, the micro-convection enables relatively uniform Li+ distribution at the LMA interface and enhances the mass transport in the electrolyte, which can suppress the Li dendrite growth even at 5.0 mA cm-2.