AM30 Mg-AI-LDH

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

Basically, Mg–Al layered double hydroxide (LDH) coatings are prepared on the surface of micro-arc oxidation (MAO) coated magnesium (Mg) alloys at a high temperature or a low pH value. This scenario leads to the growth rate of LDH coating inferior to the dissolution rate of the MAO coating. This in turn results in limited corrosion resistance of the composite coating. In this study, a Mg–Al LDH coating on MAO-coated Mg alloy AZ31 is prepared through a water bath with a higher pH (13.76) at a lower temperature (60 °C). FE-SEM, EDS, XRD, XPS, and FT-IR are applied to analyze the surface morphology, chemical compositions, and growth process. Electrochemical polarization, electrochemical impedance spectroscopy (EIS) and hydrogen evolution tests are employed to evaluate the corrosion resistance of the samples. The results disclose that the MAO coating is completely covered by the nanosheet-structured LDH coating with a thickness of approximately 3.8 μm. The corrosion current density of the MAO-LDH composite coating is decreased four orders of magnitude in comparison to its substrate; the presence of a wide passivation region in anodic polarization branch demonstrates its strong self-healing ability, indicating the hybrid coating possesses excellent corrosion resistance. The formation mechanism of the LDH coating on the MAO-coated Mg alloy is proposed. Furthermore, the cytocompatibility is assessed via an indirect extraction test for MC3T3-E1 pre-osteoblasts, which indicates an acceptable cytocompatibility of osteoblasts for the composite coating.

Two-dimensional (2D) membrane-based ion separation technology has been increasingly explored to address the problem of lithium resource shortage, yet it remains a sound challenge to design 2D membranes of high selectivity and permeability for ion separation applications. Zeolitic imidazolate framework functionalized modified layered double hydroxide (ZIF-8@MLDH) composite membranes with high lithium-ion (Li^+) permeability and excellent operational stability were obtained in this work by in situ depositing functional ZIF-8 nanoparticles into the nanopores acting as framework defects in MLDH membranes. The defect-rich framework amplified the permeability of Li^+, and the site-selective growth of ZIF-8 in the framework defects bettered its selectivity. Specifically speaking, the ZIF-8@MLDH membranes featured a high permeation rate of Li^+ up to 1.73 mol m^−2 h^−1 and a desirable selectivity of Li^+/Mg^2+ up to 31.9. Simulations supported that the simultaneously enhanced selectivity and permeability of Li^+ are attributed to changes in the type of mass transfer channels and the difference in the dehydration capacity of hydrated metal cations when they pass through nanochannels of ZIF-8. This study will inspire the ongoing research of high-performance 2D membranes through the engineering of defects. The zeolitic imidazolate framework functionalized modified layered double hydroxide (ZIF-8@MLDH) composite membranes with superior structural stability and Li^+ permeability are prepared by selectively growing ZIF-8 nanoparticles in the framework defects of the MLDH membrane. The tailor-made ZIF-8@MLDH membrane has a large Li^+ permeability of up to 1.73 mol m^-2 h^-1 and a high Li^+/Mg^2+ selectivity of 31.9, which exceed most of the current 2D lamellar membranes.

Osteosarcoma (OS) tissue resection with distinctive bactericidal activity, followed by regeneration of bone defects, is a highly demanded clinical treatment. Biodegradable Mg-based implants with desirable osteopromotive and superior mechanical properties to polymers and ceramics are promising new platforms for treating bone-related diseases. Integration of biodegradation control, osteosarcoma destruction, anti-bacteria, and bone defect regeneration abilities on Mg-based implants by applying biosafe and facile strategy is a promising and challenging topic. Here, a black Mn-containing layered double hydroxide (LDH) nanosheet-modified Mg-based implants was developed. Benefiting from the distinctive capabilities of the constructed black LDH film, including near-infrared optical absorption and reactive oxygen species (ROS) generation in a tumor-specific microenvironment, the tumor cells and tissue could be effectively eliminated. Concomitant bacteria could be killed by localized hyperthermia. Furthermore, the enhanced corrosion resistance and synergistic biofunctions of Mn and Mg ions of the constructed black LDH-modified Mg implants significantly facilitated cell adhesion, spreading and proliferation and osteogenic differentiation in vitro, and accelerated bone regeneration in vivo. This work offers a new platform and feasible strategy for OS therapeutics and bone defect regeneration, which broadens the biomedical application of Mg-based alloys.

In recent years, arsenic contamination in aquatic environments has become increasingly severe. Hydrotalcites are widely used for arsenic removal, but challenges remain regarding their removal efficiency and recyclability. To enhance the adsorption performance of Hydrotalcite-like(LDH) for arsenic and facilitate solid-liquid separation, in this study, magnetic Fe3O4 was combined with LDH and thermally modified using microwave treatment to obtain microwave-assisted modification of magnetic LDH(WFe3O4@MAF-LDH), which was used for arsenic removal. The results showed that WFe3O4@MAF-LDH effectively removed arsenic over a wide pH range. The adsorption of As(III) and As(V) by the material was well described by pseudo-first and pseudo-second-order kinetic models. Thermodynamic analysis confirmed that the adsorption process was spontaneous, and the maximum adsorption capacity of WFe3O4@MAF-LDH for As(III) was 217.62 mg/g. The inhibitory effect of coexisting anions on As(III) adsorption followed the order of SO42- > NO3- > Cl-. In addition, the material demonstrated strong and stable pollutant adsorption properties. Mechanically, arsenic removal by WFe3O4@MAF-LDH involved electrostatic interactions, ion exchange, coordination reactions, and oxidation-reduction reactions, as evidenced by material characterization means. Density Functional Theory(DFT) calculations revealed hydrogen bonding between H3AsO3/HAsO42- and WFe3O4@MAF-LDH, with MAF-LDH playing an important role in arsenic removal. In summary, WFe3O4@MAF-LDH demonstrated excellent arsenic removal, structural stability, and environmental friendliness, providing a valuable reference for the development of efficient adsorption treatment materials for arsenic-containing wastewater.

Layered double hydroxides (LDH) have been shown to be effective adsorbents, but their utility for the treatment of per- and polyfluoroalkyl substances (PFAS) in water has not been fully explored. In this study, the adsorption of 9 PFAS on hydrotalcite (HT), a type of LDH, was investigated using reaction solutions with environmentally relevant PFAS concentrations. The adsorption of individual PFAS by HT depended upon a range of factors, including the temperature used to pre-treat (i.e., calcine) the HT, aging conditions, and the presence of anions in the solution. HT calcined near 400 °C most effectively adsorbed PFAS, but its ability to adsorb PFAS was sensitive to storage conditions. The adsorption of CO2 and moisture from air, which likely resulted in the re-intercalation of CO32- into the interlayer regions of HT, was observed to reduce PFAS adsorption and may explain performance loss over time. The adsorption trend among 9 PFAS and the influence on this process by Cl-, NO3-, SO42-, and CO32- indicated that adsorption occurred via a combination of ion exchange, electrostatic attraction, and hydrophobic interactions, although the relative importance of each mechanism deserves further investigation. During this study, we also demonstrated for the first time that HT can be thermally regenerated at 400 °C without affecting its ability to adsorb PFOS and PFBA. Overall, our results suggest that HT may serve as an effective alternative for PFAS treatment.

A series of Ni-Mg-Al hydrotalcite-derived mixed metal oxides with different Ni/Mg ratios were prepared by the coprecipitation method followed by calcination at 600 °C. The hydrotalcite-like materials, as well as their calcined forms, were characterized with respect to structure (XRD, UV-Vis DRS), chemical composition (ICP-OES), textural parameters (low-temperature N2 sorption), dispersion of nickel species (H2-chemisorption) and nickel species reducibility (H2-TPR). Moreover, the process of hydrotalcite-like materials’ thermal transformation to mixed metal oxide systems in air and argon flow was studied by the TG-DTA method. The activity of the studied catalysts in the reaction of ammonia decomposition increased with an increase in nickel content in the samples. It was shown that nickel species incorporated into the Mg-Al oxide matrix segregated under conditions of reduction in a flow of H2/Ar mixture with the formation of metallic nickel crystallites of the average size of about 10 nm. The size of nickel crystallites was practically no change in the subsequent reduction cycles and resulted in increased catalytic activity in comparison to larger crystallites of metallic nickel (20.2–23.6 nm) deposited on Al2O3 and MgO.

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

No abstract available

Layered Double Hydroxide (LDH) coatings were synthesized on as-cast, T4 (solution treatment), and T6 (aging treatment) AZ91 magnesium alloys using a hydrothermal method. XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) analyses showed that the large β-phases in as-cast AZ91 initially promoted LDH growth via galvanic corrosion, but later compromised coating integrity. In contrast, T6 and T4 alloys, with refined microstructures, formed uniform and compact LDH coatings. Corrosion resistance was enhanced in T6 and T4 alloys, as evidenced by higher impedance from EIS (Electrochemical Impedance Spectroscopy), and HER (Hydrogen Evolution Reaction) tests, due to the formation of dense LDH layers.

No abstract available

No abstract available

No abstract available

To improve the corrosion resistance of the AZ31B magnesium alloy, a micro-arc oxidation coating (MAO) was fabricated on the magnesium alloy, and a MgAlCe-doped layered double hydroxide (LDH) film was prepared on the surface of the MAO coating using the hydrothermal method. The LDH film was composed of LDH sheets, which can not only cover the pores of the MAO coating but also form a rough surface structure. With the increase of hydrothermal temperature from 80 to 110 °C, the average diameter of LDH sheets decreased from 2.5 to 0.75 μm; the average distance between the LDH sheets decreased from 3 μm to 0.39 μm; and the coverage rate increased from 56.5 % to 99.8 %. The further increase of hydrothermal temperature led to an inverse tendency of these structural parameters. The hydrophobicity increases with the increase of roughness factor. LDH sheets with small sizes and distances have a large roughness factor and excellent hydrophobicity. The corrosion resistance increases with the increase of the LDH coverage rate. The sample with an LDH coverage rate of 99.8 % had excellent corrosion resistance, with Ecorr of −0.311 V, Icorr of 2.967 × 10−9 A·cm−2, and the Z0.01Hz of 9.76 × 105 Ω·cm2.

No abstract available

No abstract available

No abstract available

In this study, oxide coatings with layered double hydroxide (LDH) nanosheets were prepared on AZ91 magnesium alloy by a one-step low-voltage microarc oxidation (MAO) process. The microstructure and composition of the coatings were characterized using SEM, EDS, XRD, FT-IR, and XPS. The corrosion protection performance of the coatings was evaluated by electrochemical analysis and hydrogen evolution tests. The results showed that oxide coatings with Mg-Al-LDH nanosheets are successfully produced by microarc oxidation at a voltage of less than 100 V. The coating with a higher density of Mg-Al LDH nanosheets exhibited enhanced corrosion resistance. Moreover, after modification with stearic acid, the coatings displayed high hydrophobicity and corrosion resistance.

Organic coatings are used as one of the most effective strategies for the corrosion protection of metals. Nowadays, due to environmental regulations, the use of water-based coatings has become essential compared to solvent-based ones. However, their application to magnesium alloys remains largely unexplored due to their high reactivity with water. In the present work, a phosphate-functionalized waterborne binder is applied to AZ31B magnesium alloy. The surface has been modified by four different pre-treatments, respectively: (i) mechanical grinding, (ii) pickling, (iii) conventional conversion treatment, and (iv) a novel conversion treatment based on layered double hydroxides (LDH). The most promising pre-treatments are selected to explore their synergy with a biobased waterborne binder, containing CeO2 nanoparticles as a corrosion inhibitor. The morphology and composition of the different systems are studied, prior to and after corrosion tests in NaCl solution, by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Results obtained by electrochemical impedance spectroscopy (EIS) in NaCl solution have revealed not only that LDH performs better than the conventional conversion treatment but also the synergy between LDH pre-treatment and CeO2 nanoparticles when two organic layers are used.

Magnesium and its alloys are interesting materials but they have low corrosion resistance. Magnesium-aluminium double layered hydroxide (Mg-Al LDH) coatings were prepared on AZ31 alloy by hydrothermal method at 50 °C, 70 °C and 90 °C at different reaction times (3 h, 6 h and 24 h). The coatings were characterized by scanning electron microscope (SEM) with energy dispersive X-ray spectroscope (EDS), X-ray diffraction (XRD) and potentiodynamic polarization measurements in 0.15 M NaCl. The optimum conditions for the preparation of the coating included a temperature of 90 °C and a reaction time of 24 h, as the coating was composed of Mg-Al LDH and exhibited the highest corrosion resistance.

The aim of the present study was to investigate the effect of the concentration of precursors in the reaction mixture on the microstructure and electrochemical corrosion properties of MgAl-LDH coatings deposited on magnesium alloy AZ31. The concentrations of precursors Mg(NO 3 ) 2 and Al(NO 3 ) 3 were set to 0.10, 0.05, and 0.02 M and 0.10, 0.05, and 0.02 M, respectively. The deposition time ranged from 12 to 48 hours. The microstructure of LDH coatings and their chemical composition were characterized by scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS). Electrochemical corrosion properties were evaluated using potentiodynamic polarization in 0.15 M NaCl solution.

No abstract available

No abstract available

No abstract available

No abstract available

In situ formation of layered double hydroxides (LDH) on metallic surfaces has recently been considered a promising approach for protective conversion surface treatments for Al and Mg alloys. In the case of Mg-based substrates, the formation of LDH on the metal surface is normally performed in autoclave at high temperature (between 130 and 170 °C) and elevated pressure conditions. This hampers the industrial application of MgAl LDH to magnesium substrates. In this paper, the growth of MgAl LDH conversion coating directly on magnesium alloy AZ91 at ambient conditions (25 °C) or elevated temperatures is reported in carbonate free electrolyte for the first time. The direct LDH synthesis on Mg alloys is enabled by the presence of organic chelating agents (NTA and EDTA), which control the amount of free and/or hydroxyl bound Mg2+ and Al3+ in the solution. The application of the chelating agents help overcoming the typical technological limitations of direct LDH synthesis on Mg alloys. The selection of chelators and the optimization of the LDH treatment process are supported by the analysis of the thermodynamic chemical equilibria.

No abstract available

Hepatocellular carcinoma (HCC) is one of the leading contributors to cancer‐related death because the immunosuppressive tumor microenvironment (TME) limits its therapeutic efficacy. Gasdermin (GSDM)‐mediated pyroptosis is a new programmed cell death that can boost antitumor immune responses. However, inducing efficient pyroptosis to reverse the immunosuppressive TME is challenging. Herein, layered double hydroxide‐coated magnesium (Zn‐LDH@Mg) implants are designed and constructed as alternating magnetic field (AMF)‐activated pyroptosis inducers to induce highly effective pyroptosis in cancer cells. The powerful eddy‐thermal effects of Zn‐LDH@Mg implants markedly amplify pyroptosis in malignant cells through the Caspase‐1/GSDMD‐dependent canonical pathway. Moreover, Mg2+ and pyroptosis synergistically activate T cells (especially CD8+ T cells) and enhance the infiltration of immune‐supportive cells. This innovative strategy not only significantly suppresses the proliferation of the primary tumor but also stimulates the immune response to further enhance the efficacy of immune checkpoint inhibitors and impede the progression of distant tumors. This work not only emphasizes the importance of surface engineering strategies for the preparation of novel pyroptosis inducers but also highlights the effectiveness of the strategy in reversing the immunosuppressive TME to enhance immunotherapy, providing a new approach for the rational design of bioactive materials to increase the efficacy of immunotherapy.

No abstract available

This study provides a detailed characterization of the AA5083 aluminum alloy, surface, and interface over 6 months of immersion in seawater, employing techniques such as SEM/EDX, GIXRD, μ-Raman and XPS. The purpose was to evaluate the evolution of the biomineralization process that occurs on the Al–Mg alloy. By investigating the specific conditions that favor the in situ growth of layered double hydroxide (LDH) during seawater immersion as a result of biomineralization, this research provides insights into marine biomineralization, highlighting its potential as an innovative and sustainable strategy for corrosion protection.

MgAl LDH–NO2 (LDH–NO2) hybrid self-repairing microcapsules were synthesized, and the physical and chemical properties such as microscopic morphology and core ratio of microcapsules were characterized. The effects of microcapsule mixing on the setting time, compressive strength and self-repairing performance of cementitious materials were characterized, and the corrosion protection performance of microcapsules mixed in cementitious materials was revealed. The findings demonstrated that the microcapsules exhibited excellent dispersing properties, and the setting time of the composite cement slurry was prolonged to some extent by the mixed microcapsules. The self-repairing performance of the cementitious material was enhanced by the mixed microcapsules. In comparison to the control specimen, the chloride saturated uptake capacity of the samples mixed with 3 wt% and 6 wt% hybrid microcapsules was improved by 25.94% and 45.57%, respectively. The corrosion inhibition efficiency (η) of self-repairing microcapsules is between 82.28 and 91.04%, and the η of hybrid microcapsules is between 97.47 and 99.04%. The micro-scratches of the coating were effectively repaired by the hybrid microcapsules, the corrosive ion Cl− within the matrix is absorbed and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NO}}_{2}^{{-}}$$\end{document} is released. The corrosion protection of steel bar was significantly improved by the cooperative function of microcapsules and LDH–NO2.

To address the issue of metal corrosion in marine environments, we developed a nanofiller with corrosion resistance and UV absorption capabilities. This nanofiller is prepared using a coprecipitation hydrothermal method and consists of TTA intercalated into an LDH structure with an outer layer containing CeO2, forming a layered double hydroxide (LDH) sandwich structure nanocontainer. TTA can be successfully released in corrosive environments, and the filler exhibits excellent corrosion inhibition and interlayer ion exchange properties. Polarization curve analysis shows that the corrosion inhibition efficiency of MgAl-TTA LDH@CeO2 reaches 89.87%. After immersion in a corrosion solution for 60 days, the EP/MgAl-TTA LDH@CeO2 coating maintains a high impedance of 3.88 × 108 Ω·cm2 in the low-frequency region, which is 166 times that of the pure EP coating. Even after 240 h of UV aging, the impedance of the EP/MgAl-TTA LDH@CeO2 coating remains high at 3.10 × 108 Ω·cm2 (20,000 times higher than the pure EP coating). This significantly enhances the coating’s anti-aging and corrosion resistance, providing a feasible method for creating new long-lasting corrosion-resistant coatings in challenging environments.

No abstract available

No abstract available

: Layered Double Hydroxides (LDHs) coatings were developed for corrosion protection of AZ31 Mg alloy. LDH coatings were fabricated under co-precipitation conditions and applied under hydrothermal conditions. Two different systems Zn-Al LDH and Li-Al LDH were studied. Specimens were post-treated via immersion for 2 h at 45 ºC in Na 2 WO 4 ·H 2 O or LiNO 3 baths respectively, to produce Zn-Al LDH(W) and Li-Al LDH(Li). The characterization of the coatings was carried out by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The corrosion process was studied by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). Surface was also evaluated by water drop contact angle and paint adhesion test by using an epoxy primer. The characterization of the coating revealed two-layered coatings with a denser inner layer and a flaky outer layer. Both coatings improved the corrosion resistance of the AZ31 alloy. Loading with inhibitor further increased the corrosion resistance by one order of magnitude (Bare substrate, Z 10mHz ⁓ 102 Ω cm2 ; LDH, Z 10mHz ⁓ 103-4 Ω cm2 ; LDH-inhibitor, Z 10mHz ⁓ 105 Ω cm2 ).

In the present study, MgFe layered double hydroxide (LDHs) coatings were prepared on the surface of Mg–Nd–Zn–Zr (JDBM) alloy by a chemical conversion method, and the effects of the pH value (pH = 8, 10 and 12) of the prepared solution on the morphology, corrosion resistance and biocompatibility of the coatings were studied. The thickness of the Mg–Fe LDHs coatings was 43.79 ± 3.65 μm (pH = 8), 46.18 ± 1.05 μm (pH = 10) and 28.71 ± 4.05 μm (pH = 12), respectively. The corrosion rate of the JDBM matrix in simulated body fluid was 3.1 ± 0.1 mm/year, the LDHs coating significantly slowed down the corrosion process. When the pH of the mixed solution was 10, the Mg–Fe LDHs coatings exhibited the lowest corrosion rate (0.07 ± 0.008 mm/year). The cell experiment results indicate the Mg–Fe LDHs coating significantly enhances the cell viability of both EA.hy926 cells and A7r5 cells. At a 50% extract concentration, the cell viability for the JDBM alloy was 70% (EA.hy926) and 61% (A7r5), respectively, while the cell viability for the Mg–Fe LDHs coatings exceeded 95% for both EA.hy926 cells and A7r5 cells. In addition, the hemolysis ratio of the coated sample is about 1.7%, much lower than that of the JDBM alloy (46.7%), meeting the clinical requirements for medical materials with a hemolysis ratio below 5%. Based on the above results, the corrosion resistance and in vitro biocompatibilities of the JDBM alloy are significantly improved by the Mg–Fe LDHs coatings.

No abstract available

No abstract available

Magnesium, is a biodegradable metal, is regarded as a promising candidate for biomedical applications. To modify the degradation behavior of magnesium and improve its osteo-compatibility, chemical conversion and spin coating methods were combined to develop a di-ammonium hydrogen phosphate/poly ether imide (DAHP/PEI) co-coating system. The DAHP pretreatment was employed to enhance the attachment between PEI coatings and the magnesium substrate, meanwhile it could serve as another bioactive and anti-corrosion layer when PEI coatings break down. Surface characterization, electrochemical tests, and short-term immersion tests in DMEM were performed to evaluate DAHP/PEI coatings. Electrochemical measurements showed that DAHP/PEI coatings significantly improved the corrosion resistance of pure magnesium. No obvious changes of the chemical compositions of DAHP/PEI coatings occurred after 72 hours of immersion in DMEM. An in vitro cytocompatibility study confirmed that viability and LDH activity of MG-63 cells on DAHP/PEI coatings showed higher values than those on DAHP pretreated layer and pure magnesium. DAHP pre-treated layer could still enhance the ALP activity of MG-63 cells after the degradation of PEI in DAHP/PEI coatings. Besides that, the in vitro cellular response to the treated magnesium was investigated to gain knowledge on the differentiation and proliferation of human adipose-derived stem cells (hADSCs). Cell distribution and morphology were observed by fluorescent and SEM images, which demonstrated that DAHP/PEI coatings facilitated cell differentiation and proliferation. The high level CICP production of hADSCs on DAHP/PEI coatings indicates the great potential for osteogenic differentiation when combined with the OsteoImage results. Positive results from long-term cytocompatibility and proliferation tests indicate that DAHP/PEI coatings can offer an excellent surface for hADSCs cells.

No abstract available

Layered double hydroxides (LDHs) or hydrotalcite-like compounds have attracted great attention for the delivery of anticancer drugs due to their 2D structure, exhibiting a high surface-to-volume ratio and a high chemical versatility. The drug is protected between the layers from which it is slowly released, thus increasing the therapeutic effect and minimizing the side effects associated to nonspecific targeting. This work aimed to design LDHs with Mg and Al (molar ratio of 2/1) in brucite-like layers, which retained fluorouracil (5-FU; 5-FU/Al = 1, molar ratio) in the interlayer gallery as the layers grow during the co-precipitation step of the synthesis. To rationally control the physicochemical properties, particularly the size of the crystallites, the aging step following the co-precipitation was performed under carefully controlled conditions by changing the time and temperature (i.e., 25 °C for 16 h, 100 °C for 16 h, and 120 °C for 24 h). The results revealed the achievement of the control of the size of the crystals, which are gathered in three different agglomeration systems, from tight to loose, as well as the loading degree of the drug in the final organic–inorganic hybrid nanomaterials. The role played by the factors and parameters affecting the drug-controlled release was highlighted by assessing the release behavior of 5-FU by changing the pH, solid mass/volume ratio, and ionic strength. The results showed a pH-dependent behavior but not necessarily in a direct proportionality. After a certain limit, the mass of the solid diminishes the rate of release, whereas the ionic strength is essential for the payload discharge.

No abstract available

The advancement of highly efficient and cost-effective electrocatalysts for electrochemical water splitting, along with the development of triboelectric nanogenerators (TENGs), is crucial for sustainable energy generation and harvesting. In this study, a novel hybrid composite by integrating graphitic carbon nitride (GCN) with an earth-abundant FeMg-layered double hydroxide (LDH) (GCN@FeMg-LDH) was synthesized by the hydrothermal approach. Under controlled conditions, with optimized concentrations of metal ions and GCN, the fabricated electrode, GCN@FeMg-LDH demonstrated remarkably low overpotentials of 0.018 and 0.284 V and 0.101 and 0.365 V at 10 and 600 mA/cm2 toward the hydrogen evolution (HER) and oxygen evolution (OER) reactions, respectively, in 1.0 M KOH. Furthermore, we leveraged the potential of the GCN@FeMg-LDH composite to develop a high-performance TENG suitable for practical electronic applications. The resulting GCN@FeMg-LDH-based TENG device, sized at 3 × 4 cm2, demonstrated a substantial current output of 52 μA and a voltage output of 771 V. Notably, this TENG device exhibited an instantaneous power output of 5780 μW and exceptional stability, enduring over 15 000 cycles. Thus, this study concludes that the GCN@FeMg-LDH composite emerges as a superior candidate for applications in water splitting and TENGs, exhibiting significant promise for advancing clean energy technologies, in addition to lowering greenhouse gas emissions.

In the present study, the surface of AZ31 Mg alloy was pretreated by etching in nitric acid and plasma electrolytic oxidation (PEO). Then Mg-Al layered double hydroxide (Mg-Al/LDH) was synthesized on the pretreated surface of substrates via hydrothermal treatment to increase the corrosion resistance. The effect of surface pretreatment (etched substrate and PEO layer) on LDH formation, structure, and corrosion resistance was investigated. Ben-zoxazine resin (thermosets), has been used for coatings, however, the high curing temperature limits their applications. For this purpose, a new bio-based benzoxazine resin with a lower curing temperature (160 ◦ C) was developed to be applicable for Mg alloys. Phenol (Phloretic acid), diol (Dodecandiol), and amine (mono-ethanolamine) were used to synthesize innovative benzoxazine with exchangeable ester functions and self-healing ability. This resin was further used for post-treatment of LDH samples. The morphology, chemical composition, and crystalline structure of LDH samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion resistance of the coatings was investigated by salt spray test as well as electrochemical impedance spectroscopy (EIS). The LDH layer on the etched substrates showed better corrosion resistance than the LDH on PEO layer due to having a thicker inner layer (11.8 ± 0.2 μ m and 7.0 ± 0.6 μ m for LDH on the etched substrate and PEO layer, respectively). Post-treatment of samples with benzoxazine resin showed the effective capability of this polymeric coating for enhancing the corrosion resistance of Mg alloy substrate. This benzoxazine coating increased the corrosion resistance of the coating/substrate system around 10 4 times in comparison to the bare substrate. Moreover, it was observed that the LDH layer can increase the adhesion and compatibility of the substrate with benzoxazine resin. These results were confirmed by EIS and cross-cut adhesion tests experimentally as well as theoretical calculations of the adsorption energy of benzoxazine molecule to the LDH layer using Density Functional Theory (DFT).

In this paper, a series of porous hierarchical Mg/Al layered double hydroxides (named as LDH, TTAC-MgAl-LDH, CTAC-MgAl-LDH, and OTAC-MgAl-LDH) was synthesized by a simple green hydrothermal method using wormlike micelles formed by salicylic acid and surfactants with different carbon chain lengths (0, 14, 16, and 18) as soft templates. BET, XRD, FTIR, TG, and SEM characterizations were carried out in order to investigate the structure and properties of the prepared materials. The results showed that the porous hierarchical CTAC-MgAl-LDH had a large specific surface area and multiple pore size distributions which could effectively increase the reaction area and allow better absorption capability. Benefiting from the unique architecture, CTAC-MgAl-LDH exhibited a large adsorption capacity for sulfonated lignite (231.70 mg/g) at 25 °C and a pH of 7, which outperformed the traditional LDH (86.05 mg/g), TTAC-MgAl-LDH (108.15 mg/g), and OTAC-MgAl-LDH (110.51 mg/g). The adsorption process of sulfonated lignite followed the pseudo-second-order kinetics model and conformed the Freundlich isotherm model with spontaneous heat absorption, which revealed that electrostatic adsorption and ion exchange were the main mechanisms of action for the adsorption. In addition, CTAC-MgAl-LDH showed a satisfactory long-time stability and its adsorption capacities were still as high as 198.64 mg/g after two adsorption cycles.

Although artificial bone repair scaffolds, such as titanium alloy, bioactive glass, and hydroxyapatite (HAp), have been widely used for treatment of large‐size bone defects or serious bone destruction, they normally exhibit unsatisfied bone repair efficiency because of their weak osteogenic and angiogenesis performance as well as poor cell crawling and adhesion properties. Herein, the surface functionalization of MgAlEu‐layered double hydroxide (MAE‐LDH) nanosheets on porous HAp scaffolds is reported as a simple and effective strategy to prepare HAp/MAE‐LDH scaffolds for enhanced bone regeneration. The surface functionalization of MAE‐LDHs on the porous HAp scaffold can significantly improve its surface roughness, specific surface, and hydrophilicity, thus effectively boosting the cells adhesion and osteogenic differentiation. Importantly, the MAE‐LDHs grown on HAp scaffolds enable the sustained release of Mg2+ and Eu3+ ions for efficient bone repair and vascular regeneration. In vitro experiments suggest that the HAp/MAE‐LDH scaffold presents much enhanced osteogenesis and angiogenesis properties in comparison with the pristine HAp scaffold. In vivo assays further reveal that the new bone mass and mineral density of HAp/MAE‐LDH scaffold increased by 3.18‐ and 2.21‐fold, respectively, than that of pristine HAp scaffold. The transcriptome sequencing analysis reveals that the HAp/MAE‐LDH scaffold can activate the Wnt/β‐catenin signaling pathway to promote the osteogenic and angiogenic abilities.

The principal possibility to grow layered double hydroxide (LDH) at ambient pressure on plasma electrolytic oxidation (PEO) treated magnesium alloy AZ91 in the presence of chelating agents is demonstrated for the first time. It avoids hydrothermal autoclave conditions, which strongly limit wide industrial application of such coating systems, and the presence of carbonate ions in the electrolyte, which lead to the formation of “passive” non-functionalizable LDH. A combination of chelating agents (sodium diethylenetriamine-pentaacetate (DTPA) and salicylate) were introduced to the treatment solution. The role of each additive and the influence of treatment bath composition on the LDH formation processes are discussed. A synergistic effect of DTPA and salicylate during LDH formation is discovered and its possible explanation is proposed.

Based on the evaluation of sustained‐release performance in aqueous solution, sodium dodecyl sulfate (SDS) and phosphate ions were selected as two anionic corrosion inhibitors with excellent inhibition properties. Using hydrothermal treatment, co‐precipitation, and anion exchange techniques, LDH‐P + S coatings containing both SDS and phosphate and MgAl‐LDH coatings intercalated with silicate, phosphate, and SDS were successfully fabricated. The microstructure and composition of the various LDH coatings were characterized using XRD, FT‐IR, XPS, SEM, and EDS. The corrosion resistance and durability of the LDH coatings were assessed using EIS, PDP, and hydrogen evolution tests. All four LDH coatings demonstrated good corrosion protection, with the LDH‐P + S coating exhibiting slightly superior corrosion resistance compared with the others. Single‐frequency EIS analysis was conducted to evaluate self‐healing properties, indicating that the LDH‐P + S coating performed the best in restoring protection. The superior self‐healing behavior is primarily ascribed to the combined contribution of phosphate‐induced passivation and SDS‐mediated adsorption barrier formation.

No abstract available