Rct Value Research Articles

Comparative electrochemical properties of polyaniline/carbon quantum dots nanocomposites modified screen-printed carbon and gold electrodes

In this study, carbon quantum dots (Cdots) synthesized from a pencil graphite precursor using a bottom-up method were incorporated into polyaniline (PANI) to form Cdots-PANI nanocomposite. Cdots, PANI and Cdots-PANI nanocomposites were characterized using the Fourier-Transform infrared spectroscopy (FT-IR), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The FT-IR spectra of graphene and Cdots show the emergence of a peak at 3500 cm−1, which was initially absent in graphene, after the formation of Cdots, among other peaks. The peak at 3500 cm−1 and the stretching vibration at 1647 cm−1 suggest the presence of –OH and C=C in the Cdots. The FT-IR spectra of PANI/Cdots and PANI show that the peaks in PANI shifted to higher wavenumbers after composite formation. Similarly, the UV–visible spectra of the PANI/Cdots composite revealed a hypsochromic shift of the characteristic PANI peaks at 320 and 600 nm to 300 and 560 nm, respectively. Electrochemical characterization of Cdots, PANI and Cdots-PANI nanocomposites was done with screen-printed carbon electrodes (SPCE) and screen-printed gold electrodes (SPAuE) modified with the nanomaterials and the nanocomposites. The electrochemical properties of the as-synthesized nanomaterials and the nanocomposite were investigated with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in 10 mM K3[Fe(CN)6] solution using the bare screen-printed electrodes and the modified electrodes. The modified electrodes gave higher anodic peak current (Ipa) responses and lower charge transfer resistance (Rct) values in the redox probe than the bare electrodes. The SPCE-Cdots-PANI nanocomposite-modified electrode exhibited better redox potentials, faster electron transfer kinetics, larger surface area, and greater stability than the bare electrodes and the other modified electrodes. The outstanding electrochemical properties of SPCE-Cdots/PANI underscores its potentials as a sensitive electrochemical sensor for a wide range of analytes.

Synergistic effect of silica/polypyrrole nanocomposites synthesized by hydrothermal method using rice husk as a silica source for corrosion protection

Rice husk, a plentiful agricultural waste, is a natural and environmentally friendly silica reservoir. In this study, a hydrothermal synthesis was employed to produce silica/polypyrrole nanocomposites, with the primary objective of developing corrosion-resistant materials. The nanocomposites are comprehensively characterized using XRD, FTIR, FESEM, and electrochemical studies. The results confirmed the successful formation of a silica/polypyrrole nanocomposite and revealed that the adsorption of polypyrrole molecules onto silica clusters controls the formation of larger silica nanoparticles. Pure silica exhibits spherical particles ranging from 500 to 1 μm. A low concentration of polypyrrole results in nanoparticles with dimensions ranging from 100 to 200 nm, while a higher concentration leads to reduced silica nanoparticles with sizes 10–20 nm. Aggregation of spherical nanoparticles is more prominent in silica/polypyrrole nanocomposites than pure silica nanoparticles. The nanocomposites of silica/polypyrrole, namely SP-1, SP-2, and SP-3, demonstrated significantly higher corrosion resistance (Rct) values of 36613 Ω, 44536 Ω, and 49060 Ω, respectively, in comparison to the pure silica (19540 Ω). The corrosion rates of pure silica, SP-1, SP-2, and SP-3 were determined to be 1.2687 mm/yr, 0.4715 mm/yr, 0.4681 mm/yr, and 0.3042 mm/yr, respectively. Silica exhibits remarkable chemical stability and exceptional corrosion resistance, whereas polypyrrole is a conducting polymer endowed with distinctive electrical characteristics. These constituents can be synergistically combined within a nanocomposite matrix, enhancing corrosion resistance. The synthesized nanocomposite exhibits considerable promise as a corrosion-resistant coating agent, presenting a sustainable remedy for corrosion mitigation in different industrial contexts.

Enhancing surface area, morphology, and electrocatalytic activity favouring triiodide reduction via surface sulfurization of metal oxide

Herein, a direct anionic exchange method was employed using Thioacetamide (TAA) and Phosphorous Pentasulfide (P2S5) by facile hydrothermal method. The preliminary results confirm that the sulfurization leads to amorphization and formation of MoS2. BET analysis demonstrates the substantial improvement in the surface area from 72.046 m²/g for pristine MoO3 to 104.402 m²/g, and 140.802 m²/g, for TAA and P2S5 treated MoO3 respectively, was achieved upon sulfurization. Cyclic Voltammetry (CV) studies show an excellent triiodide reduction ability in LiI/I redox system which is due to the improvement in electrocatalytically active sites and stability across the CE/electrolyte interface. The lower charge transfer resistance (Rct) values obtained from Electrochemical impedance spectroscopy (EIS) confirm the effective charge carrier transport that improved the conductivity across electrode/electrolyte interface. The power conversion efficiency (PCE) measured under our lab conditions found an improvement for pristine MoO3 i.e. 0.78% to a maximum PCE of 5.48% and 4.12% for the P2S5 and TAA sulfurized MoO3 respectively. In general, this work highlights the use of phosphorous pentasulfide which can also be utilized for direct anionic exchange with the advantage of phosphorous content in resultant products which could greatly improve various physio-chemical properties of the material.

Impedimetric transduction from a single-step thin film nanoporous aluminum oxide as a DNA sensing electrode

A two-step anodization process has been widely used to grow a perfectly arranged Anodic Aluminum Oxide (AAO) nanoporous with high regularity and circularity. However, this method requires more time and electricity cost since the second step anodization will be conducted more than a couple of hours up to 24 h to obtain a perfect hexagonally arranged AAO. Besides, the usage of toxic chromic acid to remove the rough surface after the first anodization is not recommended. To solve this issue, a single-step of anodization method to grow AAO at 15 °C in 0.3 M of oxalic acid at 40 V for 1 h has been proposed. In this study, the growth AAO thin film will be tested as a DNA biosensor electrode. Prior to that, instead of using toxic chemicals, couple of drops of phosphoric acid solutions were used to treat the rough, uneven surfaces by promoting hydroxyl groups while at the same time widening and revealed the underneath pores. The AAO thin film is ready for the next step of surface modification without a second anodization step. Surface chemical functionalization using 3-aminopropyl-triethoxysilane (APTES) and glutaraldehyde is performed to immobilize the aminated-ssDNA probe on the surface. The electrochemical impedance technique is employed to monitor the changes in each layer of surface modifications. The charged transfer resistance (Rct) values are linearly increased with each new additional layer on the AAO surfaces during each step of surface modification and with the increase in ssDNA complementary target concentrations (10 fM-10 μM). From the performance test, the single-step AAO thin film electrode has shown great results in functioning as a DNA biosensor through a selectivity test. It has the capability to differentiate the complementary sequences from the single mismatched target with 3-fold.

A disposable sensor based on one-pot synthesized tungsten oxide nanostructure-modified screen printed electrodes for selective detection of dopamine and uric acid.

Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO3) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO3 composition was confirmed with XRD, Raman,FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO3 nanostructures via the drop-casting method clearly reduced the Rct value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity. As a result, SUWO3/SPCEs enabled highly sensitive non-enzymatic detection of DA (LOD: 51.4nM and sensitivity: 127µAmM-1cm-2) and UA (LOD: 253nM and sensitivity: 55.9µAmM-1cm-2) at low concentration. Lastly, SUWO3/SPCEs were tested with synthetic urine, in which acceptable recoveries for both molecules (94.02-105.8%) were obtained. Given the high selectivity, the sensor has the potential to be used for highly sensitive simultaneous detection of DA and UA in real biological samples.

The facile production of Fe2O3-biochar electrocatalyst for methanol oxidation reaction

In this study, the facile-green method was applied for the production of electroactive composite anode material. For this purpose, biochar was produced via pyrolysis of Pinus nigra (PN) sawdust in a stainless-steel reactor at 300, 400 and 500 °C with 10 °C/min heating rate. The Fe2O3 particles were fabricated via the green synthesis method. The Fe2O3-biochar electrocatalyst was operated on Ni foam electrode and the potential application as an anode for methanol fuel cell was investigated in an alkaline medium. Field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller analysis (BET), and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR) were used to characterize the morphology of the electrocatalyst samples. The electrochemical measurements of electrocatalyst samples were achieved via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and chronoamperometry (CA). The enlarged surface area of biochar enabled the formation of more electroactive sites for methanol electrooxidation and favorable structures of biochar could support to increased electrocatalytic activity of catalysts for methanol oxidation and produce favorable matrices for Fe2O3 loading. The obtained results demonstrate that the electrooxidation of methanol occurred at 0.36 V. The favorable structures of biochar acted as a support, enhancing the electrocatalytic activity of Fe2O3 for methanol oxidation. The electrocatalyst demonstrated remarkable activity with almost 4 A g−1 current density at 0.55 V. The Rct values were 0.73 Ω and 0.45 Ω at 0.55 V, for Ni foam and Ni foam/Fe2O3-biochar, respectively. Long-term measurements demonstrated that the Ni foam/Fe2O3-biochar catalysts was remarkably stable, with a 4 % difference in current before and after the CA analysis.

Strengthening the mechanical properties and corrosion resistance of Ni[sbnd]W coatings by PDA-functionalized h-BN nanosheets

PDA-functionalized h-BN nanomaterials (Ph-BN) were used to reinforce the electrodeposited NiW coatings. Compared with the h-BN nanomaterial, Ph-BN has better dispersion in the plating solution, which can effectively improve the mechanical and corrosion resistance of the coating. Compared with the NiW coating, the microhardness value of the Ni-W/Ph-BN coating (662.8 Hv) was increased by 33.47 % and the friction coefficient (0.382) was reduced by 41.86 %. This is due to the special ceramic composite layered structure of Ph-BN namely the combination of flexible unit PDA structure and rigid unit h-BN structure, which will synergistically hinder the shedding of the coating during the friction process and help to improve the wear resistance of the coating. The Rct value of Ni-W/Ph-BN is 34,500 Ω•cm2, which is 105.36 % higher compared to NiW coating. Ni-W/Ph-BN also has the smallest corrosion rate (0.0465 mm•a−1), which is 45.74 % lower relative to NiW coating. The uniformly dispersed Ph-BN nanosheets in the coating prolong the corrosion path for corrosive ions. Besides, the PDA has the effect of anchoring Fe2+/ Fe3+, which will be beneficial for the composite coating corrosion resistance improvement.

Enhancing the electrochemical and photovoltaic performance of hexagonal tin disulfide nanoflakes for dye-sensitized solar cells counter electrode by Tantalum dopant

The ongoing effort to stabilize and enhance dye-sensitized solar cells (DSSCs) efficiency has prompted the solar society to adopt innovative strategies. The counter electrode (CE) plays a crucial role, with platinum (Pt) being effective but expensive. Transition metal dichalcogenides (TMDs) like Tin sulphide (SnS2) show promise as alternatives to Pt. In this work, Tantalum (Ta)-doped SnS2 hexagonal nanoflakes have been synthesized by the hydrothermal method. Characterization using X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) revealed the impact of dopants on these nanoflakes. XRD, Raman, and HRTEM confirmed the hexagonal structure of nanoflakes. Electrochemical impedance spectroscopy (EIS) indicated a reduced charge transfer resistance (Rct) value of 1.51 Ω. Cyclic voltammetry (CV) analyses confirmed the improved electrocatalytic activity and superior redox reaction. Therefore, Ta dopant SnS2-based CE offers cost-effective and enhanced power conversion efficiency (PCE) in DSSC.

Hydrothermal synthesis of ZnO@MoTe2 nanocomposite as excellent electrocatalyst for hydrogen evolution reaction (HER)

The comprehension of novel fundamental inquiries about the design of electrocatalysts is of paramount importance in enhancing the availability of renewable energy resources and advancing the progress of exceptionally durable and effective nonprecious electrocatalysts for the process of water splitting. Enhancing the capacity of renewable energy storage systems through the usage of nonprecious nanocomposites for efficient H2O splitting holds the potential to foster a more sustainable and environmentally conscious society, hence mitigating the impact of global warming. The nanocomposite exhibits proficient catalytic kinetics for the HER process owing to the enhanced accessibility of MoTe2′s most active zones. The physical property of the nanocomposite was established through in-process characterization using different analytical techniques. In a basic environment, the ZnO@MoTe2 combination exhibited a significant value for the generation of hydrogen using electrocatalysts based on ZnO@MoTe2, which was a 34 mV dec-1 Tafel slope. The nanocomposite exhibited a higher turn-over frequency rate (TOF) of 2.4 s−1 than pure materials. The ZnO@MoTe2 nanocomposite displays a higher surface area of 1125 cm2 and a low Rct value of 93 Ω. The electrocatalyst exhibits exceptional stability and durability. During 50 h in an alkaline environment, the application of chronopotentiometry reveals no substantial decrease in potential. The utilization of nanocomposite based electrocatalysts has been shown to provide efficient quick charge kinetics, a noteworthy observation. The results of this study offer a novel, reliable and effective electrocatalyst that has potential applications in the advancement of electrocatalytic devices for hydrogen gas (H2) production. These devices can be developed employing cost-effective technologies and naturally occurring materials widely available worldwide.

Study of Performance Graphene Oxide Modification of LiFePO4/C Material for The Cathode of Li-Ion Batteries

The need for energy storage is increasing rapidly along with technological development. Lithium ion batteries are one of the energy storages that are in great demand due to their high specific capacity and energy density, discharge voltage of 3.4 volts, and environmental friendliness. LiFePO4 is a lithium-ion battery cathode material with a high specific capacity of 170 mAh/g and a discharge voltage of about 3.4 V, thermal stability, high energy density, environmentally friendly, and easy to obtain. However, it has low electrical conductivity and poor ion diffusion, which hinders energy storage. Carbon modification is a method that has the advantage of reducing particle size and preventing agglomeration in nanoparticles, so this method is widely researched to improve lithium ion diffusion coefficient and conductivity in lithium ion batteries. This study aims to describe the effect of GO modification on the characterization of LiFePO4/C-GO composite material and LiFePO4/C-GO composite material battery performance as a lithium ion battery cathode material. In this study, it can be seen that the addition of GO in LiFePO4 cathode material can improve battery performance. The LiFePO4/C-GO-10 cathode obtained the most effective results with the lowest Rct value of 95.21 Ω and the highest conductivity value of 14.3×10-6 S/cm indicating the best electron transport. The Rct value decreased with the addition of GO, and the conductivity value increased with the addition of GO.

Study of peripheral dose from low-dose CT to adaptive radiotherapy of postoperative prostate cancer.

The increasing use of computed tomography (CT) for adaptive radiotherapy (ART) has raised concerns about the peripheral radiation dose. This study investigates the feasibility of low-dose CT (LDCT) for postoperative prostate cancer ART to reduce the peripheral radiation dose, and evaluates the peripheral radiation dose of different imaging techniques and propose an image enhancement method based on deep learning for LDCT. A linear accelerator integrated with a 16-slice fan-beam CT from UIH (United Imaging Healthcare, China) was utilized for prostate cancer ART. To reduce the tube current of CT for ART, LDCT was acquired. Peripheral doses of normal-dose CT (NDCT), LDCT, and mega-voltage computed tomography (MV-CT) were measured using a cylindrical Virtual Water™ phantom and an ion chamber. A deep learning model of LDCT for abdominal and pelvic-based cycle-consistent generative adversarial network was employed to enhance the image quality of LDCT. Six postoperative prostate cancer patients were selected to evaluate the feasibility of low-dose CT network restoration images (RCT) by the deep learning model for ART. The three aspects among NDCT, LDCT, and RCT were compared: the Hounsfield Unit (HU) of the tissue, the Dice Similarity Coefficient (DSC) criterion of target and organ, and dose calculation differences. In terms of peripheral dose, the LDCT had a surface measurement point dose of approximately 1.85 mGy at the scanning field, while the doses of NDCT and MV-CT were higher at 22.85 mGy and 29.97 mGy, respectively. However, the image quality of LDCT was worse than NDCT. When compared to LDCT, the tissue HU value of RCT showed a significant improvement and was closer to that of NDCT. The DSC results for target CTV between RCT and NDCT were also impressive, reaching up to 94% for bladder and femoral heads, 98% for rectum, and 94% for the target organ. Additionally, the dose calculation differences for the ART plan based on LDCT and NDCT were all within 1%. Overall, these findings suggest that RCT can provide an effective alternative to NDCT and MV-CT with similar or better outcomes in HU values of tissue and organ damage. More testing is required before clinical application.

Biomass Derived High Porous Carbon via CO2 Activation for Supercapacitor Electrodes

In this study, we systematically study the efficient production method and electrochemical characteristics of activated carbons (AC) derived from rice husk (RH) and walnut shell (WS). In particular, the effectiveness of physical activation using carbon dioxide (CO2) was investigated and compared with the more common chemical activation method using potassium hydroxide (KOH). The results show that the KOH–activated samples have remarkable specific capacities, reaching 157.8 F g−1 for RH and 152 F g−1 for WS at 1 A g−1. However, the rate capability of AC obtained via KOH decreases significantly as the scanning rate increases, retaining only 51.5% and 68% of their original capacities for RH–KOH and WS–KOH, respectively, at 20 A g–1. In contrast, CO2–activated samples show a superior rate performance with a capacity retention of 75.6% for WS and 80% for RH at the same current density. In addition, electrochemical impedance spectroscopy (EIS) analysis shows that AC obtained via CO2 has a lower charge transfer resistance compared to its KOH counterparts. CO2–activated RH and WS electrodes show Rct values of 0.1 Ω and 0.24 Ω, respectively, indicating improved ion transport kinetics and surface area utilization. These results highlight the importance of activation techniques in tailoring the electrochemical behavior of biomass–derived carbon. This study not only expands the understanding of the interaction between activation, morphology, and performance but also indicates the potential of CO2 activation as an environmentally friendly and efficient alternative. As the field of sustainable energy storage advances, this work provides valuable guidance for the development of high–performance supercapacitor electrodes with less environmental impact.

Highly Wrinkled Porous Polypyrrole for the Enhancement of the Performance of an Fe2S3-Fe2O3/poly-O-amino Benzenethiol Supercapacitor from a Basic Medium

In this study, O-amino benzenethiol (OABT) was oxidized in one pot using Fe(NO3)3 to produce a novel Fe2S3-Fe2O3/poly O-amino benzenethiol (POABT), which showed a highly uniform morphology. At the same time, from SEM analysis, highly wrinkled porous polypyrrole (Ppy) and porous ball-like POABT structures prepared from the K2S2O8 route were evidenced by SEM and TEM analyses. A nanocomposite pseudo-supercapacitor (SC) was fabricated using Fe2S3-Fe2O3/POABT, and its performance was tested with and without incorporating Ppy in the paste. The results indicate that Ppy significantly increased the specific capacitance (CS) values, indicating an enhancement in charge storage. At a current density of 0.2 A/g, the CS values were 44 F/g and 161 F/g for the paste without and with Ppy, respectively. Additionally, the E was calculated, and the incorporation of Ppy resulted in a significant increase in E, reaching 30 W.h.kg−1; this was significantly higher than the value of 8.18 W.h.kg−1 observed without Ppy materials. This effect is likely due to the improved charge transfer facilitated by the presence of Ppy, as evidenced by the Nyquist plot, where the Rct values were 1.1 Ω and 2.1 Ω with and without Ppy, respectively. Overall, the low cost and significant technical advantages of this capacitor make it a promising candidate for commercial applications.

MXene based electrocatalyst: CoS2@Ti3C2Tx composite for hydrogen evolution reaction in alkaline media

The worldwide need for hydrogen (H2) fuel generation through electrolysis is significant. The challenge of selecting a suitable electrocatalytic material, on the other hand, is highly complicated, since it involves discovering a stable, cost-effective choice that is widely accessible. Non-noble metal-based electrocatalysts are being studied for their potential to display attractive electrochemical water splitting (EWS) behaviour especially in alkaline media. Researchers are evaluating their ability to provide increased electrical conductivity, reduced overpotential, and greater density, which are all required for practical implementation. Herein, we present wet chemical-based synthesized MXene (Ti3C2Tx) incorporated cobalt-sulfide (CoS2) electrocatalyst for hydrogen evolution reaction (HER) in alkaline medium. As-prepared catalyst shows; very low overpotential value (286 mV) to reach 20 mA/cm2 current density, lower Tafel slope value of 78 mV/dec, higher electrochemical surface area (ECSA) 495 cm2, as well as a lower charge transfer resistance (Rct) value of 115 Ω. Such electrochemical features support this composition as a novel and robust electrocatalyst for HER toward its practical usage for energy storage and conversion systems.

Emulsion-assisted polyaniline grown on molybdenum diselenide nanoflowers for efficient counter electrode application in dye-sensitized solar cells

ABSTRACT Molybdenum diselenide (MoSe2) is often composed with conducting polymers like polyaniline (PANI) to lower the stacking and increase the active sites for catalysis. The method of polymerization and the concentration of monomer play a significant role in the growth of PANI nanostructures over the MoSe2 surface. Here, MoSe2-PANI nanocomposites have been synthesized with different molar concentrations of the monomer in the emulsion of chloroform and distilled water using ammonium persulfate (APS) as the initiator. The increased surface area of the composite MPAN (1:1) compared to pristine MoSe2, as observed from the FESEM and BET study, is fruitful for counter-electrode application in dye-sensitized solar cells (DSSC). The lower Rct values for the MPAN (1:1) and increased current in cyclic voltammetry further approved the suitability of the MoSe2-PANI as a counter electrocatalyst. The counter electrodes against N719 dye-sensitized TiO2 photoanode in DSSC yielded the best results for MPAN (1:1), generating an efficiency of 6.45%.

New benzisoxazole derivative: A potential corrosion inhibitor for mild steel in 0.5 M hydrochloric acid medium -insights from electrochemical and density functional theory studies

6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. HCl (FPBH), a substituted benzisoxazole derivative, was prepared from isonipecotic acid and characterized using various spectroscopic techniques. Using electrochemical examinations such as potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopic (EIS) technique, the corrosion mitigation capabilities of this compound for mild steel (MS) in 0.5 M HCl medium were investigated. Theoretical studies were performed using quantum chemical calculations and density functional theory (DFT). PDP results exhibited the mixed-type behavior of FPBH and showed a maximum efficiency of 94.5 % at 1 × 10−3 M. The development of a protective adsorbed layer of FPBH decreases the corrosion current density (icorr) and corrosion rate (CR). The EIS technique revealed that the rise in the charge transfer resistance (Rct) values and reduction in the thickness of the double-layer capacitance (Cdl) reflected the drop in corrosion rate. The adsorption of FPBH took place through physisorption by conforming Langmuir's isotherm. The DFT method was performed on the optimized structure of FPBH to get additional evidence on the action mode of FPBH with the metal surface.

Corrosion behavior of 7B04 aluminum alloy under the synergistic effect of Lacticaseibacillus paracasei and Acinetobacter lwoffi

Microbially influenced corrosion (MIC) is a multifaceted phenomenon that is influenced by the synergistic activity of various bacterial species that thrive within biofilms. The present study aims to investigate the impact of interspecies relationships on the corrosion behavior of aluminum alloy (Al alloy). To achieve this, cultures of Lacticaseibacillus paracasei (L. paracasei) and Acinetobacter lwoffi (A. lwoffi) were mixed and analyzed. The electrochemical experimental findings indicated that the 7B04 Al alloy exhibited the lowest Rct value and the highest corrosion current density when immersed in the mixed system. The utilization of surface analysis techniques, such as scanning electron microscopy and stereomicroscope, had led to the discovery of a significant number of corrosion pits in the mixed system. This finding suggested that the corrosion phenomenon was more severe than previously anticipated. The growth curve analysis revealed a synergistic interaction among the mixed bacterial species. The co-cultivation of A. lwoffi and L. paracasei resulted in increased growth activity of L. paracasei in comparison to its growth in a single system. The occurrence of dominant colonies and the development of biofilms were identified as the primary factors contributing to localized corrosion. Furthermore, the combined action of the two bacterial strains exhibited a synergistic effect that exacerbated the corrosion process.

Developing core-shell silica nanoparticles to create multifunctional coating with excellent antireflection, enhanced antifogging and anticorrosion performances

How to fabricate a multifunctional coating with controllable ultralow refractive index (RI), high antifogging and anticorrosion performances by a facile method is still one of the great challenges. In this work, a simple and time-saving approach involving a microwave-assisted sol-sel process was developed to fabricate a novel core-shell structured silica nanoparticle sol by co-condensation of perfluorodecyltriethoxysilane (F-DTOS) and tetraethoxysilane (TEOS) and self-condensation of F-DTOS. Results suggest that both the co-condensations and self-condensations not only give a layer of low surface energy –C10H4F17 groups on the silica particles but also enlarge the hybrid silica particle size, providing more and larger voids to form the high porosity. After spinning the silica nanoparticles on the substrate, the obtained optical coating exhibits the controllable ultralow refractive index (RI) and outstanding transparency. The minimum RI and maximum transmittance of our developed coating is up to ~1.04 and ~100 %, respectively. Moreover, because of the high porosity and the presence of low surface energy –C10H4F17 groups in the coating, the coating has the high hydrophobicity (water contact angle ~108.8°), which not only makes it excellent antifogging performance but also affords it high-efficient anticorrosion property. After immersion in a 3.5 wt% NaCl solution for 7 days, the Rct value of the coating could be higher than 7.3 × 104 Ω cm2. It is believed that our developed method used to fabricate such multifunctional coating does not need any costly equipments, complex steps and time-consuming, making it well suited for industrial application.

Effect of Al2O3-MWCNTs on anti-corrosion behavior of inorganic phosphate coating in high-temperature marine environment

Chemically bonded aluminum phosphate coating modified with Al2O3-MWCNTs was prepared for anti-corrosion in high-temperature marine environment. α- Al2O3 was successfully and conveniently coupled to the multi-walled carbon nanotubes by surface modification. Then the hybrid materials mixed with coating materials were applied on heat-resistant steel using high-pressure airless spraying. The success of the hybridization was verified by characterizing the composition structure and morphology of Al2O3-MWCNTs. Simultaneously, adhesion, electrochemical, and scanning electron microscopy (SEM) experiments were conducted to characterize the protective performance of the coating under different ablation times. One noteworthy phenomenon showed by the thermogravimetric analysis results is that the initial decomposition temperature of Al2O3-MWCNTs was increased by 100 °C compared with pure MWCNTs, which provided a basis for the application of the ceramic coatings in oxidation-resistant environment at 600 °C. The results of adhesion experiments showed that the dry bonding force of the ceramic coating with Al2O3-MWCNTs added on the substrate /coating interface was 3 times higher than that of the pure coating. The coating had the best surface quality following ablation at 600 °C thanks to Al2O3-MWCNTs, which gave it a denser mosaic structure on the outside and a three-dimensional mesh structure on the interior. This structure provided outstanding shielding properties and additional electron channels. Additionally, the Rct value was 34.7 kΩ.cm2 after 100 h of high temperature ablation, which was 345 times of that without added coating. In general, the results showed that the corrosion resistance of the coating with Al2O3-MWCNTs as the reinforcing phase was still maintained at a high level.

Carbon Nanowalls as Anode Materials with Improved Performance Using Carbon Nanofibers.

In this paper, a new synthesis of carbon nanofibers (CNFs)/carbon nanowalls (CNWs) was performed to improve the characteristics of anode materials of lithium-ion batteries by using the advantages offered by CNWs and CNFs. Among the carbon-based nanomaterials, CNWs provide low resistance and high specific surface area. CNFs have the advantage of being stretchable and durable. The CNWs were grown using a microwave plasma-enhanced chemical vapor deposition (PECVD) system with a mixture of methane (CH4) and hydrogen (H2) gases. Polyacrylonitrile (PAN) and N,N-Dimethyl Formamide (DMF) were stirred to prepare a solution and then nanofibers were fabricated using an electrospinning method. Heat treatment in air was then performed using a hot plate for stabilization. In addition, heat treatment was performed at 800 °C for 2 h using rapid thermal annealing (RTA) to produce CNFs. A field emission scanning electron microscope (FE-SEM) was used to confirm surface and cross-sectional images of the CNFs/CNWs anode materials. Raman spectroscopy was used to examine structural characteristics and defects. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and constant current charge/discharge tests were performed to analyze the electrical characteristics. The synthesized CNFs/CNWs anode material had a CV value in which oxidation and reduction reactions were easily performed, and a low Rct value of 93 Ω was confirmed.