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MnMo–NiS were synthesized for electro-oxidizing ethylene glycol (EG), glycerol (GLY), and 5-hydroxymethylfurfural (HMF), achieving faradaic efficiencies of 97.5%, 98.6%, and 99.2%, and yield rates of 615.7, 475.5, and 333.9 μmol h−1 cm−2. In situ Raman spectroscopy and multi-step chronoamperometry reveal that Ni3+–O is the active site. [ABSTRACT FROM AUTHOR]

The V-α-Ni(OH)2/GO nanoarrays prepared by simple coprecipitation show excellent catalytic properties in urea electro-oxidation, ascribed to the dual modulation of d-orbital electron regulation and ultrathin hierarchical nanostructure construction, which is caused by the introduction of V. [ABSTRACT FROM AUTHOR]

This study aims to explore the influence of control parameters from the perspective of the amorphous ceramic coating formation process. Three preparation processes were preferred based on the thickness, appearance and corrosion resistance of the coatings by orthogonal experiment. The surface morphology, cross-sectional structure, phase composition and micro-hardness of PEO coatings were examined using scanning electron microscopy (SEM)/Energy dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD) and hardness measurement techniques. Findings indicate that voltage exerts the most significant impact on coating thickness and appearance, whereas the influence of other parameters becomes more pronounced as the voltage increases. Three amorphous ceramic coatings prepared in 20 min with thicknesses of 27.4 μm, 83.2 μm and 193.3 μm increased the surface hardness of 6061 aluminium alloy by 6–8 times, and decreased the corrosion current density of 6061 aluminium alloy by 3 orders of magnitude in 1 mol L−1 HCl solution. Moreover, the thickening of the coating primarily occurs within a few minutes after the voltage reaches its peak, and high frequency and low duty ratio are prerequisites for better appearance under higher voltage conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

A SiC-SiO 2 nano-composite coating was prepared via a novel liquid-phase plasma-assisted particle deposition and sintering (LPDS) method to enhance the oxidation resistance of the Ti-6Al-4V alloy. For comparison, a conventional plasma electrolytic oxidation (PEO) ceramic coating is fabricated on the Ti-6Al-4V alloy. The microstructure and formation mechanisms of both ceramic coatings were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results indicated that the thickness of the SiC nano-composite coating (∼40 μm) increased significantly by 285 % compared to the PEO coating (∼14 μm). The microstructural evolution and isothermal oxidation performance of the PEO and SiC-SiO 2 nano-composite coating were comparatively investigated at 800 °C. After 100 h, the thickness gain of the SiC-SiO 2 nano-composite coating (∼14 μm) was lower than that of the PEO coating (∼26 μm). The improved oxidation performance is primarily attributed to the outermost layer containing abundant SiC nanoparticles, which transform into SiO 2 during the oxidation process and effectively inhibiting the inward penetration of oxygen. [ABSTRACT FROM AUTHOR]

In this study, composite coatings of TiO 2 /Fe3+ were developed by incorporating Fe(NO 3) 3 into TiO 2 -based coatings, produced via plasma electrolytic oxidation (PEO) on unalloyed titanium. The ability of these coatings to photodegrade methylene blue (MB) under visible light was investigated. The morphology, chemical composition, and optical properties of the PEO coatings were characterized using various techniques, including X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, and UV–Vis diffuse reflectance. All coatings exhibited a porous structure, with phase analysis revealing the formation of anatase and rutile phases during the coating process. The coatings were also found to be hydrophobic. Increasing the concentration of Fe(NO 3) 3 in the composite coatings from 0 to 0.1 g/L resulted in a decrease in the optical band gap energy from 3.05 eV to 2.95 eV. The PEO coating with 0.10 g/L of Fe(NO 3) 3 showed the highest photocatalytic activity (PA), achieving 70 %. This improvement in PA is likely due to the formation of a heterojunction, which effectively separates electron/hole pairs. [ABSTRACT FROM AUTHOR]

Partial electro‐oxidation using renewable electricity offers a sustainable route for valorizing glycerol, a major by‐product of biofuel production. This study introduces a bimetallic electrode with nanostructured platinum dendrites on nickel foam (Pt/NiF), achieving a peak geometric current density of 235 mA cm−2 and a Pt‐mass normalized current density of 3.71 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$ for glycerol electro‐oxidation at 0.92 V versus a reversible hydrogen electrode (RHE) in 3 m KOH electrolyte containing 1 m glycerol, outperforming most previously reported Pt‐containing catalysts. The Pt/NiF electrode demonstrates over 92% cumulative selectivity toward C3 products, with 64% selectivity for lactic acid at 0.65 V versus RHE over 5 h of testing. This research also highlights the role of chemical oxidation pathways (isomerization and rearrangements) in converting glycerol to lactic acid. After 5 h at 0.65 V versus RHE, the Pt/NiF electrode maintains 35% of its initial current density, plateauing at 12.2 mA cm−2 (0.15 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$), with performance loss likely due to surface poisoning by carbon‐based reaction intermediates/byproducts or passivating platinum (hydr)oxide species. These findings pave the way for developing low‐platinum group metal catalysts with high glycerol oxidation affinity and highlight the importance of considering chemical transformations during catalyst evaluation and reactor design. [ABSTRACT FROM AUTHOR]

[Display omitted] This paper develops a new measurement method to answer the question: How does one measure the interfacial tension of adsorbed droplets? This measurement is based on the placement of a bubble at a water|organic interface. To prove the concept, a bubble was formed by pipetting gas below the water|1,2-dichloroethane interface. Our values agree well with previous reports. We then extended the measurement modality to a more difficult system: quantifying interfacial tension of 1,2-dichloroethane droplets adsorbed onto conductors. Carbon dioxide was generated in the aqueous phase from the electro-oxidation of oxalate. Given carbon dioxide's solubility in 1,2-dichloroethane, it partitions, a bubble nucleates, and the bubble can be seen by microscopy when driving the simultaneous oxidation of tris(bipyridine)ruthenium (II), a molecule that will interact with CO 2 .−. and provide light through electrochemiluminescence. We can quantify the interfacial tension of adsorbed droplets, a measurement very difficult performed with more usual techniques, by tracking the growth of the bubble and quantifying the bubble size at the time the bubble breaks through the aqueous|1,2-dichloroethane interface. We found that the interfacial tension of nanoliter 1,2-dichloroethane droplets adsorbed to an electrified interface in water, which was previously immeasurable with current techniques, was one order of magnitude less than the bulk system. [ABSTRACT FROM AUTHOR]

This review systematically evaluates the research and applications of metal mesh‐based catalysts for CO oxidation. CO is a hazardous gas that affects human health and the environment. Traditional cordierite‐based catalysts have drawbacks such as complex preparation, high costs, poor stability, and limited catalytic activity, necessitating exploration of alternative solutions. Monolithic metal mesh‐based catalysts, using metal substrates like Ti, Cu, Fe, FeCrAl, stainless steel, Al and Ni, could address these problems effectively. Generally, each metal mesh requires specific pretreatments to roughen surface and facilitate the loading of active species. Plasma electrolytic oxidation is particularly effective for Ti and Al mesh. This results in a monolithic metal mesh‐based catalyst with uniform surface distribution and fully exposed active species. The review also summarizes in‐situ preparation strategies for metal mesh‐based catalysts and their progress in CO oxidation. Finally, the development potential of metal mesh‐based catalysts is discussed, emphasizing the significant challenges and future prospects for industrial applications. [ABSTRACT FROM AUTHOR]

A major challenge in the application of ceramic materials is a trade‐off between strength and toughness. In this work, hierarchically structured ceramic coatings (HSCCs) are fabricated to address this challenge. HSCCs feature a dual‐layer micron‐scale structure built on a “brick‐mortar” nanoscale structure, which is achieved by changing the crystalline and amorphous phase ratio during plasma electrolytic oxidation (PEO). It is found that HSCCs with homogeneous interfaces exhibit high thermal stability up to 700 °C and a 65% improvement in shear strain resistance compared to conventional crystalline coatings (CCCs). This improvement is attributed to the stabilizing effect of atoms on the boundaries of the enhancement phase and the facilitating effect on the deformation of the compliant phase. The hierarchical structure effectively leverages the plasticity of the compliant phase and the strength of the enhancement phase facilitated by the homogeneous interface. This work proposes a feasible approach for improving the toughness of ceramic functional composites and mitigating their susceptibility to brittle fracture. [ABSTRACT FROM AUTHOR]

Magnesium alloys have gained attention as potential biodegradable metallic biomaterials due to their mechanical properties akin to human bone. However, their rapid corrosion within the body prior to full bone fracture healing presents a significant challenge. Hence, our study aimed to address their drawbacks by employing a cerium oxide/merwinite nanocomposite coating. In this investigation, we sought to enhance corrosion resistance and antibacterial properties by depositing a porous cerium oxide layer onto AZ31 magnesium alloy via plasma electrolytic oxidation (PEO), while improving biocompatibility through a secondary merwinite silicate coating applied via electrophoretic deposition (EPD). Surface morphology and chemical composition were analyzed using Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS) pre- and post-immersion in Simulated Body Fluid (SBF). Coating phases were examined through X-ray Diffraction (XRD), antibacterial efficacy was evaluated via viable cell counts in contact with Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive), and corrosion resistance was assessed using Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP) tests following SBF immersion. Furthermore, adhesion and toxicity were investigated to assess biocompatibility. The findings revealed that the composite coating exhibited a higher calcium-to-phosphate ratio (Ca/P = 1.31) along with enhanced cell adhesion, increased cell viability, reduced toxicity, and 99.99 % antibacterial activity. [ABSTRACT FROM AUTHOR]

The general trend of increasing life expectancy will consistently drive the demand for orthopedic prostheses. In addition to the elderly, the younger population is also in urgent need of orthopedic devices, as bone fractures are a relatively common injury type; it is important to treat the patient quickly, painlessly, and eliminate further health complications. In the field of traumatology and orthopedics, metals and their alloys are currently the most commonly used materials. In this context, numerous scientists are engaged in the search for new implant materials and coatings. Among the various coating techniques, plasma electrolytic oxidation (PEO) (or micro-arc oxidation—MAO) occupy a distinct position. This method offers a cost-effective and environmentally friendly approach to modification of metal surfaces. PEO can effectively form porous, corrosion-resistant, and bioactive coatings on light alloys. The porous oxide surface structure welcomes organic molecules that can significantly enhance the corrosion resistance of the implant and improve the biological response of the body. The review considers the most crucial aspects of new combined PEO-organic coatings on metal implants, in terms of their potential for implantation, corrosion resistance, and biological activity in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate the effect of plasma electrolytic oxidation (PEO) coatings and sealed PEO coatings on the corrosion resistance and cytocompatibility of a novel Mg-1Zn-0.45Ca alloy in simulated body fluid (SBF). Design/methodology/approach: The microstructure, corrosion resistance and cytocompatibility of PEO coatings and phosphate conversion-treated PEO coatings were investigated and was compared with the bare Mg alloy. Findings: The hot-extruded Mg-Zn-Ca alloy exhibit inhomogeneous microstructure and suffered from localized corrosion in the SBF. The PEO coating after phosphate conversion treatment offers enhanced protectiveness to the Mg alloy within an immersion period of up to 60 days, which is significantly improved compared with the performance of the PEO-coated Mg alloy, but the cytocompatibility was slightly decreased. Originality/value: This work offers new perspective in balancing the protectiveness and cytocompatibility of bio-materials. [ABSTRACT FROM AUTHOR]

The Laser/PEO ceramic coating was successfully prepared in situ on AZ31B magnesium alloy by laser-assisted PEO (Laser/PEO) composite process. SEM, EDS, CLSM, XRD, XPS and M − S tests were used to observe the effects of different laser power densities on the morphology, chemical composition and electronic properties of PEO ceramic coating. The corrosion behavior of PEO ceramic coating (S0) and Laser/PEO ceramic coating (S1) was systematically observed by PDP test, EIS test, SEM, EDS, XRD and XPS by long-term immersion experiments (24, 96, 168 h) in 3.5 % NaCl solution. Moreover, the effect of laser-assisted irradiation on the corrosion mechanism of PEO ceramic coating was discussed. The Laser/PEO coating (S1) possessed better long-term corrosion resistance than PEO coating (S0), which was attributed to the improvement of laser-assisted irradiation on the density, crystallinity, thickness, and corrosion-resistant phase proportion and distribution of PEO coating. [ABSTRACT FROM AUTHOR]

Oxide ceramic layers of Ti 5 Al 16 O 34 were fabricated on commercially pure titanium grade 2 substrates by plasma electrolytic oxidation in aqueous electrolyte media at a fixed 10 g/L concentration of trisodium phosphate and 25 g/L sodium aluminate. Lowering the sodium aluminate concentration to 15 g/L and 20 g/L, β-TiAl 2 O 5 and Ti 2 Al 6 O 13 components were produced under similar PEO processing conditions. The composition and structure of the PEO coatings were studied using XPS, XRD, SEM, EDS, mechanical (hardness, adhesion, and tribology), electrochemical impedance spectroscopy, and potentiodynamic polarization tests. The layers possess a polycrystalline character with minor amorphous phases, while their thicknesses varied slightly between samples with similar treatment times. The PEO coatings consist of a compact inner layer with an enriched phosphorus content of about 5–10 wt% and a porous outer layer in which phosphorus is found in less than 1 wt%. Ti 5 Al 16 O 34 coatings showed better mechanical performance regarding microhardness and corrosion resistance compared to β-TiAl 2 O 5 and Ti 2 Al 6 O 13. At a longer applied PEO process duration of 10 min, Ti 5 Al 16 O 34 layer thickness, microhardness, and corrosion current densities of 40.2 μm, 9.37 GPa, and 2.8 nA/cm2 were measured. [Display omitted] [ABSTRACT FROM AUTHOR]

There is tremendous interest in the development of highly wear‐resistant coatings for metallic materials to reduce energy loss and prolong service life. In this study, the authors propose an approach to develop nanocomposite coatings featuring deformable nanocrystals embedded in amorphous matrix for self‐lubrication and superior wear resistance. The dual‐layered nanocomposite coatings are prepared by plasma electrolytic oxidation (PEO) on a Ti‐Nb‐Ta‐Zr‐Hf (TNZTH) refractory multi‐principal element alloy (RMPEA) and commercially pure Ti (cpTi). The inner layers of PEO coatings are composed of substrate element oxides (amorphous TNZTH─O oxide or anatase TiO2), while their outer layers exhibit typical nanocomposite structures. Different from the cpTi‐based PEO coating outer layers composed of brittle rutile TiO2 nanoparticles dispersed in an amorphous matrix of SiO2 and Na2O·nSiO2, the outer layers of TNZTH‐based PEO coatings are featured by deformable Na2Zr(Hf)O3 nanocrystals heterogeneously embedded in an inhomogeneous amorphous matrix composed of TNZTH─O oxide, SiO2, and Na2O·nSiO2. As a result, the TNZTH‐based PEO coatings exhibit favorable self‐lubricating performance and superior wear resistance, while the cpTi‐based PEO coatings are completely destroyed after sliding wear. Thus, this study offers valuable insights into the design and development of self‐lubricating coatings with superior wear resistance for metallic materials. [ABSTRACT FROM AUTHOR]

Implant surgeries are increasingly challenging due to their rising number. Achieving the desired biomaterial surface properties to ensure a strong bond with human tissue is a significant issue. This study investigates the influence of ultrasound (US) during the micro-arc oxidation (MAO) process on Ti13Zr13Nb bio-alloy, an area not previously explored, to enhance titanium alloy coatings' properties for biomedical applications. Porous calcium-phosphate-based coatings were successfully deposited on Ti13Zr13Nb using MAO and ultrasound micro-arc oxidation (UMAO). Various properties such as morphology, chemical composition, topography, wettability, surface free energy, thickness, adhesion to the substrate, as well as mechanical and corrosion characteristics were thoroughly analyzed. Cytocompatibility was assessed using human osteoblasts. Using US during the MAO process increased coating roughness (up to ~ 17%), core height (up to 22%), isotropy (up to 17%), thickness (up to ~ 46%), and hardness (up to ~ 18%), depending on MAO parameters and US mode. Optimal coating performance was achieved at 136 mA, 600 s, and a sinusoidal US setting, resulting in the highest isotropy (~ 79%) and rutile quantity (2.6%), the lowest elastic modulus (~ 57 GPa), and the contact angle of ~ 70°, all of which could have contributed to enhancing osteoblast viability in vitro. This study, for the first time, underscores the importance of using the US during the MAO in tailoring the Ti13Zr13Nb for specific biomedical applications. [ABSTRACT FROM AUTHOR]

Seawater direct electrolysis (SDE) using renewable energy provides a sustainable pathway to harness abundant oceanic hydrogen resources. However, the side-reaction of the chlorine electro-oxidation reaction (ClOR) severely decreased direct electrolysis efficiency of seawater and gradually corrodes the anode. In this study, a redox-mediated strategy is introduced to suppress the ClOR, and a decoupled seawater direct electrolysis (DSDE) system incorporating a separate O2 evolution reactor is established. Ferricyanide/ferrocyanide ([Fe(CN)6]3−/4−) serves as an electron-mediator between the cell and the reactor, thereby enabling a more dynamically favorable half-reaction to supplant the traditional oxygen evolution reaction (OER). This alteration involves a straightforward, single-electron-transfer anodic reaction without gas precipitation and effectively eliminates the generation of chlorine-containing byproducts. By operating at low voltages (~1.37 V at 10 mA cm−2 and ~1.57 V at 100 mA cm−2) and maintaining stability even in a Cl−-saturated seawater electrolyte, this system has the potential of undergoing decoupled seawater electrolysis with zero chlorine emissions. Further improvements in the high-performance redox-mediators and catalysts can provide enhanced cost-effectiveness and sustainability of the DSDE system. Seawater direct electrolysis using renewable energy provides an appealing pathway to harness abundant oceanic hydrogen resources. Here, authors report a redox-mediated decoupled seawater direct electrolysis strategy to suppress the chlorine electro-oxidation side reaction. [ABSTRACT FROM AUTHOR]

By controlling the structure and composition of Pt-based nanoalloys, the ethanol oxidation reaction (EOR) performances of Pt alloy catalysts can be effectively improved. Herein, we successfully synthesis sub-10 nm PdNi@PtNi nanoparticles (PdNi@PtNi NPs) with a core–shell structure by a one-pot method. The sub 10 nm core–shell nanoparticles possess more effective atoms and exhibit a synergistic effect which can lead to a shift in the d-band center and alter binding energies toward adsorbates. Due to the synergistic effect and unique core–shell structure, the PdNi@PtNi NP catalysts exhibit excellent electrocatalytic performance for ethanol oxidation reactions in alkaline, achieving 9.30 times more mass activity and 7.05 times more specific activity that of the state-of-the-art Pt/C catalysts. Moreover, the stability of PdNi@PtNi NPs was also greatly improved over PtNi nanoparticles, PtPd nanoparticles, and commercial Pt/C. This strategy provides a new idea for improving the electrocatalytic performance of Pt-based catalysts for EORs. [ABSTRACT FROM AUTHOR]

This paper presents the results of an evaluation of corrosion properties of PEO pretreated AlMg3 aluminum alloy samples with polymer coatings obtained by dip-coating in a suspension of superdispersed polytetrafluoroethylene (SPTFE) in a solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone at different PVDF:SPTFE ratios (1:1, 1:3, 1:5, and 1:10). The electrochemical tests showed that samples with a coating formed at a ratio of PVDF to SPTFE of 1:5 possessed the best corrosion properties. The corrosion current density of these samples was more than five orders of magnitude lower than this parameter for bare aluminum alloy. During the 40-day salt spray test (SST) for samples prepared in a suspension at a PVDF:SPTFE ratio of 1:1–1:5, the formation of any pittings or defects was not detected. The PVDF:SPTFE 1:5 sample demonstrated, as a result of the 40-day SST, an increase in corrosion current density of less than an order of magnitude. The evolution of the protective properties of the studied samples was assessed by a two-year field atmospheric corrosion test on the coast of the Sea of Japan. It was revealed that the samples with the PVDF:SPTFE 1:5 coating had electrochemical parameters that remained consistently high throughout the one year of exposure. After this period, the polymer layer was destroyed, which led to a deterioration in the protective characteristics of the coatings. [ABSTRACT FROM AUTHOR]

In the current study, a HA/TiO2 composite coating is effectively fabricated on a Ti-13Nb-13Zr alloy using the plasma electrolytic oxidation (PEO) technique. Electrolytes with different Ca/P contents are selected to study the evolution of phase composition and microstructure of PEO coating. The relationship between Ca/P contents and the wear resistance and corrosion resistance of the coatings are evaluated. The Ca/P-30 g coating exhibits the best performance with Ca/P≈1.66. The average thickness and roughness of the coating manufactured by this system are about 159 µm and 1.591 µm. The HA/TiO2 coatings akin to honeycomb have analogous pore size and uniform distribution, and the phase composition is mainly anatase. Compared with the substrate, the corrosion current density decreases by 19.65% and the corrosion potential increases by 0.805 V. The findings suggest that suitable Ca/P can promote the formation of HA, which is associated with the nucleation and growth rate of HA crystal. Furthermore, the formation mechanism of HA is simulated and the effect of Ca/P on the growth of HA is discussed. The process aims to reduce the allergic and toxic reactions caused by Ti-13Nb-13Zr implants, which is of great significance for increasing the service life of titanium alloy implants and reducing the implant failure. [ABSTRACT FROM AUTHOR]

The development of efficient nonenzymatic catalysts for the electro-oxidation of glucose is vital for glucose biosensors. Herein, we report the preparation of a branch-structured catalyst comprising an amorphous/crystalline heterophase made from AuCu alloy shells and Cu2O cores (Cu2O@a/c-AuCu). The Cu2O@a/c-AuCu catalyst exhibits a good electrocatalytic activity for the electro-oxidation of glucose. The Cu2O@a/c-AuCu-based glucose biosensor shows a high sensitivity (345 μA mM−1 cm−2) and a wide concentration detection range (0.1–10 mM). The glucose detection accuracy of the Cu2O@a/c-AuCu sensor in animal serum was consistent with that of the commercial glucometer. The outcomes of this work offer insights for constructing alloy-based heterophase nanocatalysts for biosensing and biological applications. [ABSTRACT FROM AUTHOR]

This paper presents the surface treatment results of titanium, veterinary bone wedges. The functional coating is composed of a porous oxide layer (formed by a plasma electrolytic oxidation process) and a polymer poly(sebacic anhydride) (PSBA) layer loaded with amoxicillin (formed by dip coatings). The coatings were porous and composed of Ca (4.16%-6.54%) and P (7.64%-9.89% determined by scanning electron microscopy with EDX) in the upper part of the implant. The titanium bone wedges were hydrophilic (54° water contact angle) and rough (surface area (Sa):1.16 μm) The surface tension determined using diiodomethane was 68.6 ± 2.0° for the anodized implant and was similar for hybrid coatings: 60.7 ± 2.2°. 12.87 ± 0.91 µg/mL of amoxicillin was released from the implants during the first 30 min after immersion in the phosphate-buffered saline (PBS) solution. This concentration was enough to inhibit the Staphylococcus aureus ATCC 25923, and Staphylococcus epidermidis ATCC12228 growth. The obtained inhibition zones were between 27.3 ± 2.1 mm–30.7 ± 0.6 mm when implant extract after 1 h or 4 h immersion in PBS was collected. Various implant biocompatibility analyses were performed under in vivo conditions, including pyrogen test (3 rabbits), intracutaneous reactivity (3 rabbits, 5 places by side), acute systemic toxicity (20 house mice), and local lymph node assay (LLNA) (20 house mice). The extracts from implants were collected in polar and non-polar solutions, and the tests were conducted according to ISO 10993 standards. The results from the in vivo tests showed, that the implant's extracts are not toxic (mass body change below 5%), not sensitizing (SI < 1.6), and do not show the pyrogen effect (changes in the temperature 0.15ºC). The biocompatibility tests were performed in a certificated laboratory with a good laboratory practice certificate after all the necessary permissions. [ABSTRACT FROM AUTHOR]

We investigate Ag/C and Ag-Ni/C nano-powders as anode catalysts for borohydride electro-oxidation. X-ray diffraction (XRD), field emission electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) are employed to explore the structure, morphology, oxidation states and composition of the prepared electrocatalysts. The electrocatalytic performances are investigated by cyclic voltammetry (CA), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) measurements. The obtained electrochemical results confirm the better catalytic performance of Ag-Ni/C in terms of current density, stability and charge transfer resistance than Ag/C toward BH4− electro-oxidation. Among different synthesized Ag-Ni/C electrocatalysts (S-1, S-2, S-3 and S-4) with various metal loadings, the S-2 (10 wt% Ag-Ni in carbon support) catalyst displays the highest electrocatalytic activity. The CA measurement is performed for S-2 catalyst in various temperatures to find the apparent activation energy (Eapp) and the number of exchanged electrons (n) in 0.5 M NaOH + 0.01 M NaBH4 solution. We obtained n and Eapp as 2.5 at 30⁰ C and 30.6 kJ mol− 1 respectively using S-2 as anode electrocatalyst. Investigation was conducted into the catalyst loading on the surface of the glassy carbon working electrode, revealing optimal borohydride oxidation performance at a loading of 1.28 mg cm− 2. In cell performance testing, the S-2 electrocatalyst exhibited the highest open circuit voltage of 1.75 V. The Ag-Ni/C electrocatalyst, with a metal-to-carbon weight ratio of 20:80, shows potential as a promising candidate for future research as an anode material in borohydride fuel cells. [ABSTRACT FROM AUTHOR]

The biodegradability of magnesium (Mg) metal implants necessitates surface modification to mitigate the high corrosion rate in the body's physiological environment. This study focuses on synthesizing and applying a nanocomposite coating of polydimethylsiloxane-nanosized bioactive glass (PDMS-nBG) on the surface of a plasma electrolytic oxidation (PEO)-modified AZ91 Mg alloy. The PDMS-1 wt% nBG nanocomposite coating was deposited on the PEO-treated substrate using the dip-coating method. Surface and cross-sectional morphologies of the nanocomposite coatings were examined using field emission scanning electron microscopy (FESEM). Corrosion behavior of the AZ91 substrate, PEO coating, and double-layer PEO/PDMS-nBG coating was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. Results showed that the corrosion resistance and corrosion current density of Mg substrates increased and decreased from 4815 Ω.cm2 and 8.96 µA.cm− 2 to 18 MΩ.cm2 and 0.00016 µA.cm− 2 for AZ91 and PEO/PDMS-nBG coating, respectively. Additionally, the morphology and adhesion of cultured human mesenchymal cells on the PEO-modified AZ91 substrates with a single PDMS polymer coating and a PDMS-nBG nanocomposite coating were investigated using fluorescent light microscopy and FESEM. The PEO/PDMS-nBG bilayer coating effectively addressed the limitations of magnesium alloys and holds potential for biomedical applications, particularly in orthopedic implants, due to the enhanced biocompatibility and bioactivity of Mg alloys. [ABSTRACT FROM AUTHOR]

Efficcient elecctro-oxidation of 5-hydroxymethylfurfural (HMF) to produce 2,5-furandicarboxylic acid (FDCA) was achieved in a low-concentrated alkaline electrolyte over a single-atom-ruthenium supported on Co 3 O 4 (Ru 1 -Co 3 O 4). Single-atom-Ru enhances hydroxyl (OH–) adsorption, thereby improving the oxidation of HMF. The design for the Ru 1 -Co 3 O 4 catalyst enables efficient HMF-to-FDCA electrocatalysis without using strong alkaline electrolytes, which may greatly improve the profitability of HMF-to-FDCA electroccatalysis. [Display omitted] Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a sustainable strategy to produce bio-based plastic monomer, is always conducted in a high-concentration alkaline solution (1.0 mol L−1 KOH) for high activity. However, such high concentration of alkali poses challenges including HMF degradation and high operation costs associated with product separation. Herein, we report a single-atom-ruthenium supported on Co 3 O 4 (Ru 1 -Co 3 O 4) as a catalyst that works efficiently in a low-concentration alkaline electrolyte (0.1 mol L−1 KOH), exhibiting a low potential of 1.191 V versus a reversible hydrogen electrode to achieve 10 mA cm−2 in 0.1 mol L−1 KOH, which outperforms previous catalysts. Electrochemical studies demonstrate that single-atom-Ru significantly enhances hydroxyl (OH−) adsorption with insufficient OH− supply, thus improving HMF oxidation. To showcase the potential of Ru 1 -Co 3 O 4 catalyst, we demonstrate its high efficiency in a flow reactor under industrially relevant conditions. Eventually, techno-economic analysis shows that substitution of the conventional 1.0 mol L−1 KOH with 0.1 mol L−1 KOH electrolyte may significantly reduce the minimum selling price of FDCA by 21.0%. This work demonstrates an efficient catalyst design for electrooxidation of biomass working without using strong alkaline electrolyte that may contribute to more economic biomass electro-valorization. [ABSTRACT FROM AUTHOR]

The strategic design of traditional coating materials has long been pivotal in broadening their range of applications. In this work, europium‐doped TiO2 coatings are grown in situ on the surface of titanium substrate using plasma electrolytic oxidation technology. The core reaction took no more than five minutes. Incorporating europium into the coating preserved the inherent corrosion resistance of PEO coatings while imparting anticipated thermal‐sensitive luminescence capabilities. The intrinsic emission of TiO2 and the characteristic emission of Eu3+ (5D0 → 7F2) are employed as the self‐reference for the LIR thermometry. The absolute and relative temperature sensitivity of the coating reached 0.0087 K−1 and 0.739% K−1, respectively. Notably, the coating exhibited a signal discriminability of up to 5100 cm−1 and a temperature uncertainty of only 0.18 K, which is comparable to some TiO2: Eu nanoparticles. The ingenious fusion of corrosion resistance and thermal‐sensitive luminescence of the coating not only makes it a classic protective structure but also facilitates its applicability to diverse scenarios, including optical thermometry in extreme environments. [ABSTRACT FROM AUTHOR]

Platinum-based high-entropy-alloy nanoparticles (PHEA-NPs) have been attractive as electrocatalysts due to their excellent electrocatalytic properties. In this work, PHEA-NPs consisting of platinum, iron, copper, cobalt, nickel and manganese were prepared via a facile solvothermal reduction method and further examined for electro-oxidation of formic acid (FA) and glycerol (GLY). The resulting PHEA-NPs exhibited superior activity for FA and GLY electro-oxidation in acidic solutions relative to the commercial Pt/C catalyst. In contrast, PHEA-NPs showed no activity for FA oxidation and mediocre activity for GLY oxidation in alkaline electrolytes. Interestingly, the activity for FA and GLY electro-oxidation in alkaline solutions was enhanced via an acidic treatment, which was attributed to the surface enrichment of platinum element arisen from the structural re-construction of PHEA-NPs. To explore the role of the components, a series of control samples were prepared. It was found that the presence of copper, nickel, and iron is beneficial to the electro-oxidation of FA and GLY in acidic electrolytes. Further CO stripping experiments were conducted to evaluate the poisoning resistance of the samples, which correlates with the catalytic performance. It was found that PHEA-NPs exhibit superior tolerances to CO poisoning compared to Pt/C. The findings from this work may be valuable for fabricating high-performance electrocatalysts for the electro-oxidation of FA and GLY. [Display omitted] • PHEA-NPs show excellent performance for FA and GLY oxidation in acidic electrolytes. • Copper, nickel, and iron contribute played a crucial role for the superior activity. • PHEA-NPs exhibit superior tolerances to CO poisoning compared to Pt/C. • An acid treatment enhanced activities of PHEA in alkaline electrolytes. • Surface Pt enrichment was the main reason for the increased activity. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO), applied to light metals such as titanium, aluminum, and magnesium, creates a two-layer coating and has become increasingly important in metal coatings. However, due to the high voltage and temperature of the process, no online instrument could monitor the underlying mechanism. This paper presents a new image proving that the surface of PEO-coated Mg3ZnCa boiled during the process and argues that three hypotheses are involved in the PEO mechanism based on boiling caused by tolerating high voltage during the PEO process, which could explain the current‒voltage diagram of the process. Finally, nanoindentation was used to measure the elastic module and hardness of the PEO layers. The nanoindentation test results revealed the similarity of the elastic module of the outer porous layer and the primary alloy, with values of 40.25 GPa and 41.47 GPa, respectively, confirming that the outer porous layer corresponds to the cold plasma-gas phase formed during the PEO process. [ABSTRACT FROM AUTHOR]

The key to designing energy-efficient hydrogen production systems lies in the development of highly catalytic, low-cost non-precious metal catalysts, along with the substitution of high-energy-consuming oxygen evolution reactions with reactions involving easily oxidizable small molecules at the anode. In this paper, molybdates (NiMoO 4 and CoMoO 4) that grow on nickel foam are treated with vulcanization and nitriding methods, and Mo doped Ni 3 S 2 (Mo–Ni 3 S 2) and N doped CoMoO 4 (N–CoMoO 4) are prepared, respectively. Mo–Ni 3 S 2 exhibits excellent UOR activity requiring only 1.335 V to drive 100 mA cm−2. It is found that Mo–Ni 3 S 2 participated in both of the decomposition of urea (15.4 %) to form NH 3 and the oxidation reaction of urea (84.6 %) to form N 2 to keep the anodic reaction in the low potential range, avoiding the oxidation of nickel sites in the catalyst to form NiOOH. In addition, N–CoMoO 4 catalyst exhibits excellent hydrogen evolution reaction (HER) activity requiring only 67 mV to drive 100 mA cm−2. Finally, the catalysts prepared by molybdate are used to construct urea oxidation electrolytic system. The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) urea oxidation-assisted water splitting system requires only 1.47 V to achieve 100 mA cm−2, which is a voltage reduction of 180 mV compared to conventional water electrolysis systems. The system realizes high energy efficiency hydrogen production and urea wastewater purification. This work provides insights into the design of low-energy-consuming hydrogen production systems. [Display omitted] • The catalysts prepared by molybdate exhibit efficient UOR and HER activity. • Mo–Ni 3 S 2 follows a new UOR mechanism of urea decomposition and urea oxidation. • The Mo–Ni 3 S 2 (+) || N–CoMoO 4 (−) system requires only 1.47 V to afford 100 mA cm−2. • We couple UOR and HER to construct an energy-saving hydrogen production system. [ABSTRACT FROM AUTHOR]

An amorphous SiO 2 ceramic coating with a thickness of ∼72 μm is prepared within 13 min in organo-silicon electrolyte, which is stable in strong acid solutions, reducing corrosion current density of 6061 aluminum alloy by 3 orders of magnitude. With the aim to reveal influence of the electrolyte concentration, NaOH content and additive (NaPO 3) 6 on microstructure and corrosion resistance of the coatings, SEM/EDS, XRD, electrochemical tests were used to characterize their thickness, surface and cross-sectional morphology and structure, and corrosion performance prepared by using different electrolytes under the same electric control parameters. The results show that they significantly affect the surface morphology, structure and corrosion resistance of the coatings. Dilution of the electrolyte results in a significant decrease in coating thickness and surface porosity, reduction of NaOH content leads to coating thinning, increased porosity but reduced pore size. Coatings with lower porosity or smaller pore sizes are more effective in resisting corrosive media penetration for long term immersion. Whereas, the additive (NaPO 3) 6 promotes coating thickening, widening of the transition layer, which helpfully improves the corrosion resistance of the coating. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the mechanical behavior and biocompatibility of plasma electrolytic oxidation (PEO)-coated Mg–Zn–Ca alloy specimens were investigated. The coatings were synthesized by incorporating KMnO 4 and Mn 3 O 4 nanoparticles into an electrolytic solution. An indentation test revealed a significant increase in the reduced elastic modulus of the PEO coatings with incorporated Mn 3 O 4 under various loads. This increase was attributed to the higher coating thickness and reduced porosity achieved by the addition of Mn-based additives to the electrolyte. The composite PEO coatings prepared with Mn 3 O 4 nanoparticles exhibited a more pronounced reduction in elastic modulus under pressure. Wettability tests showed that the prepared coatings maintained their hydrophilic nature with water contact angles in the range of 25–63°. The presence of Mn 3 O 4 in the PEO coatings provided a conducive environment for cell viability. The enhanced biocompatibility of the composite coatings achieved by incorporating KMnO 4 into the electrolyte was particularly noteworthy. This improvement was attributed to the controlled release of Mn ions, which generates a microenvironment that favors cellular activities. The study showed that incorporating Mn 3 O 4 into PEO coatings enhances mechanical properties, preserves hydrophilicity, and improves biocompatibility, thus indicating its potential for orthopedic implant applications. [ABSTRACT FROM AUTHOR]

Magnesium as a biodegradable material offers promising results in recent studies of different maxillo-facial fracture models. To overcome adverse effects caused by the fast corrosion of pure magnesium in fluid surroundings, various alloys, and surface modifications are tested in animal models. In specified cases, magnesium screws already appeared for clinical use in maxillofacial surgery. The present study aims to compare the bone healing outcome in a non-load-bearing fracture scenario of the forehead in sheep when fixed with standard-sized WE43 magnesium fixation plates and screws with plasma electrolytic oxidation (PEO) surface modification in contrast to titanium osteosynthesis. Surgery was performed on 24 merino mix sheep. The plates and screws were explanted en-bloc with the surrounding tissue after four and twelve weeks. The outcome of bone healing was investigated with micro-computed tomography, histological, immunohistological, and fluorescence analysis. There was no significant difference between groups concerning the bone volume, bone volume/ total volume, and newly formed bone in volumetric and histological analysis at both times of investigation. The fluorescence analysis revealed a significantly lower signal in the magnesium group after one week, although there was no difference in the number of osteoclasts per mm2. The magnesium group had significantly fewer vessels per mm2 in the healing tissue. In conclusion, the non-inferiority of WE43-based magnesium implants with PEO surface modification was verified concerning fracture healing under non-load-bearing conditions in a defect model. Titanium implants, the current gold standard of fracture fixation, can lead to adverse effects linked to the implant material and often require surgical removal. Therefore, degradable metals like the magnesium alloy WE43 with plasma electrolytic oxidation (PEO) surface modification gained interest. Yet, miniplates of this alloy with PEO surface modification have not been examined in a fracture defect model of the facial skeleton in a large animal model. This study shows, for the first time, the non-inferiority of magnesium miniplates compared to titanium miniplates. In radiological and histological analysis, bone healing was undisturbed. Magnesium miniplates can reduce the number of interventions for implant removal, thus reducing the risk for the patient and minimizing the costs. [Display omitted] [ABSTRACT FROM AUTHOR]

Metoprolol is a cardioselective beta-blocker drug often used to treat hypertension, but it is considered as a hazardous organic persistent contaminant in wastewater. In this study, a 2.5 L solution of metoprolol (50 mg/L) underwent electro-oxidation in a flow-by reactor using boron-doped diamond electrodes in the batch recirculation mode. The study used multi-objective optimization and multi-criterion decision-making to determine the optimal operating parameters. The response surface methodology and a central composite rotatable design were used with three factors (pH0: 5–8, I: 2.5–4 A, and Q: 0.8–1.7 L/min) to model the chemical oxygen demand's (COD's) removal efficiency and the total organic carbon's (TOC's) removal efficiency. The experimental responses were modeled by reduced third- and second-order polynomials with determination coefficients (R2) of 0.9816 and 0.9430. The optimal operating parameters were found to be pH0 5, an I value of 3.84 A, and a Q value of 0.8 L/min with an electrolysis time of 7.5 h, resulting in a maximum COD removal efficiency of 60.8% and a TOC removal efficiency of 90.1%. The specific energy consumption was calculated as 9.61 kWh/mg of TOC, with a total operating cost of 0.77 USD/L. In conclusion, this study showed that the electrochemical process is efficient and reliable for treating wastewater containing metoprolol. [ABSTRACT FROM AUTHOR]

A novel ultra-sound assisted method was used to grow zinc-metal organic framework (Zn-MOF) film on magnesium oxide/hydroxyapatite (MgO/HA) composite layer developed using plasma electrolytic oxidation (PEO) on Mg-5Sn-0.2Mn-0.2Ca alloy. The microstructure surface roughness and microhardness tests were performed on the samples to evaluate the mechanical properties of the coatings. The electrochemical corrosion test was performed to evaluate the corrosion resistance of the coated Mg alloy. Further, an in-vitro bioactivity test was performed to study the biocompatibility and bioactivity of the coated alloy, which is an essential aspect of biomedical applications. Results showed that the MgO/HA composite coating was helpful in the in-situ growth of the Zn-MOF particles by mechanically interlocking them. Further, incorporating hydroxyapatite in the coating could also increase the bioactivity. The study also confirmed that the bi-layer coating of Zn-MOF on the MgO/HA composite layer improved the surface roughness, hardness, biocorrosion resistance, and bioactivity making it more likely to be used for orthopedic internal fixation devices. [ABSTRACT FROM AUTHOR]

Manufacturing technology has been refined and described for the fabrication of honeycomb-based bioresorbable networks for temporal bone replacement applications. Two novel techniques, digital light processing and investment casting, were utilized to produce customized, shape-optimized cellular constructs with additional orifices promoting tissue ingrowth during osteo-regeneration. For this purpose, a conventional magnesium casting alloy (AZ91) was chosen. Numerical simulations were conducted to predict the compressive behavior of the proposed biodegradable lightweight scaffolds. Spatial castings were adjusted to possess mechanical properties comparable to the ones of cortical or trabecular bones. Two kinds of protective coatings (plasma electrolytic oxidation and organic ones based on natural polyphenols from tea extract) were deposited and characterized. They can be utilized to control the degradation rate during exploitation to achieve a predictable implant lifespan. The elaborated layers aim to mitigate the rapid corrosion of magnesium substrates by prolonging their bioresorption time and thus expanding their applicability in osseointegration. To evaluate this assumption, immersion tests in phosphate-buffered saline were performed, showing better chemical resistance of PEO coating and as-cast sample (for both mass gain by below 1%), and visible increase in mass of sample coated with organic coating (increase by almost 5%). Compressive strength results from numerical approach were further validated by experimental compression tests, showing that PEO coating deteriorated compressive strength by almost 3%, and organic coating improved it by over 9%. Results achieved in numerical approach were better than expected for stiffer sample, and slightly lower for the one with bigger pores. [ABSTRACT FROM AUTHOR]

Bentazone is a broad-leaved weed-specific herbicide in the pesticide industry. This study focused on removing bentazone from water using three different methods: a two and three-dimensional electro-oxidation process (2D/EOP and 3D/EOP) with a fluid-type reactor arrangement using tetraethylenepentamine-loaded particle electrodes and an adsorption method. Additionally, we analysed the effects of two types of supporting electrolytes (Na2SO4 and NaCl) on the degradation process. The energy consumption amounts were calculated to evaluate the obtained results. The degradation reaction occurs 3.5 times faster in 3D/EOP than in 2D/EOP at 6 V in Na2SO4. Similarly, the degradation reaction of bentazone in NaCl occurs 2.5 times faster in 3D/EOP than in 2D/EOP at a value of 7.2 mA/cm2. Removal of bentazone is significantly better in 3D/EOPs than in 2D/EOPs. The use of particle electrodes can significantly enhance the degradation efficiency. The study further assessed the prediction abilities of the machine learning model (ANN). The ANN presented reasonable accuracy in bentazone degradation with high R2 values of 0.97953, 0.98561, 0.98563, and 0.99649 for 2D with Na2SO4, 2D with NaCl, 3D with Na2SO4, and 3D with NaCl, respectively. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) coating on Zr alloy was prepared, and the corrosion behavior was investigated under 400 °C/10.3 MPa steam condition. The surface morphology, roughness, element distribution, and microstructure of PEO coating after corrosion were analyzed. The results indicate that the PEO coating after corrosion presents the typical pores and pancake structure feature, and the surface roughness of PEO coating decreases after corrosion. The PEO coating corroded for 45 days shows the best electrochemical performance because the newly formed oxide gathers to repair the pores and cracks in the oxide/metal interface. The corrosion resistance of PEO coating decreases with the corrosion time increase because the microcrack in PEO coating is connected to generate a large transverse crack, and the corrosion media can access to oxidize the substrate through the crack during the long-term corrosion process. [ABSTRACT FROM AUTHOR]

Robust Cu2S‐Cu3P@C Nanomatrix electrode material has been synthesized via a two‐step process involving carbonization of Cu‐MOF, HKUST‐1, followed by simultaneous phosphorization and sulphurization of the carbonized product. This seamless approach leads to the efficient incorporation of highly active Cu2S‐Cu3P hybrid nanostructures within a conductive carbon matrix, exhibiting exceptional electrochemical glucose sensing performance. Synergistic interactions between Cu2S‐Cu3P and the carbon matrix boost glucose electro‐oxidation kinetics. The resulting Cu2S‐Cu3P@C displays a broad linear response (0.005–5 mM), low detection limit (2.3 μM), and high sensitivity (10,790 μA mM−1 cm−2), with excellent selectivity towards glucose even in the presence of interferents. This biomimetic Cu2S‐Cu3P@C nanomatrix catalyst holds promise for biosensor development in bioanalysis and clinical diagnosis. [ABSTRACT FROM AUTHOR]

Suboxidized titanium, as a promising anode for electrocatalytic oxidation reactions in wastewater treatment, presents a viable pathway to solve the challenging water pollution. However, current suboxidized titanium anodes are primarily fabricated hot pressing of by suboxidized titanium powders, further hampering their application in wastewater treatment due to high costs and complex shaping processes. To overcome these limitations, this work employs the plasma electrolytic oxidation (PEO) technology to in-situ fabricate porous TiO 2 coating precursors on commercial pure titanium substrates, followed by an annealing process to carefully reduce the TiO 2 coatings with hydrogen gas, and finally achieving the cost-effective production of high-purity Magnéli phase Ti 4 O 7 -coated electrode. The obtained Ti 4 O 7 -coated electrodes exhibit a highly ordered granular structure, good crystallinity, wide electrochemical window, and low interfacial charge transfer resistance. Importantly, the Ti 4 O 7 -coated electrodes also offer a simple fabrication process, lower energy consumption, and reduced costs compared to advanced boron-doped diamond (BDD) and bulk Ti 4 O 7 electrode. The electrochemical oxidation tests also demonstrate that Ti 4 O 7 -coated electrodes can achieve the complete degradation of 100 mg/L phenol within 240 minutes, exhibiting excellent catalytic activity and potential applications in wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

PEO constitutes a promising surface technology for the development of protective and functional ceramic coatings on lightweight alloys. Despite its interesting advantages, including enhanced wear and corrosion resistances and eco-friendliness, the industrial implementation of PEO technology is limited by its relatively high energy consumption. This study explores the development and optimization of novel PEO processes by means of machine learning (ML) to improve the coating thickness. For this purpose, ML models random forest and XGBoost were employed to predict the thickness of the developed PEO coatings based on the key process variables (frequency, current density, and electrolyte composition). The predictive performance was significantly improved by including the composition of the used electrolyte in the models. Furthermore, Shapley values identified the pulse frequency and the TiO2 concentration in the electrolyte as the most influential variables, with higher values leading to increased coating thickness. The residual analysis revealed a certain heteroscedasticity, which suggests the need for additional samples with high thickness to improve the accuracy of the model. This study reveals the potential of artificial intelligence (AI)-driven optimization in PEO processes, which could pave the way for more efficient and cost-effective industrial applications. The findings achieved further emphasize the significance of integrating interactions between variables, such as frequency and TiO2 concentration, into the design of processing operations. [ABSTRACT FROM AUTHOR]

PEO coatings are formed by subjecting a metal substrate to an electrolytic plasma discharge, resulting in the formation of a porous and rough oxide layer. Herein, the significant role of the chemical composition of the electrolyte system and additives in the formation of an oxide coating on brass alloy in the PEO process was investigated. It was observed that the coating created with 8 g/l aluminate, 1 g/l NaOH, and 1 g/l KF electrolyte had higher homogeneity than other coatings. This is because a composite oxide coating of Cu 2 O, ZnO, and AlCuO 2 was formed. Methylene Blue (MB), a widely used dye in various industries, is known to be persistent and environmentally harmful. The photocatalytic activity of the PEO coating on brass for the removal of MB was investigated under visible light exposure. According to the results, the presence of the sample produced in an electrolyte containing 8 g/l Aluminate, 1 g/l NaOH, and 1 g/l KF resulted in a degradation rate of approximately 65 % for MB photodegradation after 6 h of irradiation. The PEO-coated brass shows promising photocatalytic efficiency compared to our research group's PEO-coated TiO 2 coatings, indicating its potential as a photocatalyst. The results highlight that PEO coating on brass could be a potential candidate for photocatalytic and photoelectrochemical applications. [ABSTRACT FROM AUTHOR]

Single-crystal SiC nanoporous structure has important applications in the field of micro electromechanical systems, chemical sensors and biomedical devices. However, SiC exhibits a strong chemical inertness due to the short interatomic distance and high binding energy, making it significantly challenging to fabricate nanoporous structure. Electrolytic plasma-assisted chemical etching (EPACE) based on electrochemical anodic oxidation and high-activity electrolytic plasma etching is an ideal method for SiC nanoporous structure etching. In which, the spatial distribution of electrolytic plasma has an important impact on EPACE performance, such as etching efficiency and stability. In order to analyze the impact mechanism, this paper studies EPACE in tool electrode mounting posture of vertical and horizontal types by visual observation, real-time recording of voltage-current waveforms during processing, and the morphology analysis of SiC nanoporous structure after etching. It can be found that in the vertical etching type, EPACE can proceed stably because the workpiece immersion depth is greater than the bubble accumulation thickness. However, in the horizontal etching type, bubbles accumulate seriously between the workpiece and the liquid surface, which may cause bubble cavitation and abnormal discharge, leading to damage to the etching surface. The etching current in the vertical etching type is about 1.3 times that of the horizontal etching type, indicating that the bubble mass transfer in the vertical etching type is faster and the etching impedance is smaller, which is beneficial to improve the etching efficiency and obtain a uniform nanoporous structure. Finally, a SiC nanoporous layer with a thickness of 10.6 μm was prepared at etching time t = 50 min in vertical etching type, and the etching efficiency was 212 nm/min. In addition, the prepared nanoporous structure (nanofiber) was connected to the SiC substrate, indicating that it has a good bonding strength. [ABSTRACT FROM AUTHOR]

To improve the biological activities of titanium implant surfaces and promote efficient early bone formation, the formation of bioactive coatings that promote bone formation on titanium implant surfaces is currently an important area of research. In this study, we prepared a zinc-doped porous coating (Zn-PEO) on a titanium alloy surface via plasma electrolytic oxidation. The surface characteristics of the samples were evaluated with field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), profilometry, static contact angles and nanoscratch studies. The slow release of zinc from the coating was detected with inductively coupled plasma-mass spectrometry (ICP-MS). The corrosion resistances of the samples were evaluated via electrochemical studies. On this basis, we evaluated the biocompatibility and biological activity of the sample through in vitro cell experiments. The results confirmed that a Zn-PEO coating was successfully prepared on the surface of the titanium alloy; it exhibited a porous micro/nanomorphology, and the coating and the substrate were tightly bound. The coating increased the roughness of the titanium surface and improved the wear and corrosion resistance. More importantly, the coating promoted adhesion, proliferation, differentiation and mineralization of bone marrow mesenchymal stem cells and had good biological activity. Therefore, Zn-PEO coatings with porous structures were prepared on the surfaces of titanium implants through plasma electrolytic oxidation. The Zn- PEO coating exhibited good surface properties and biological activity and has good application prospects. [ABSTRACT FROM AUTHOR]

An artificial neural network (ANN) was developed to predict the corrosion resistance of MgO coatings produced by the plasma electrolyte oxidation process on ZX504 alloy, with experimental data from the Taguchi method for training and performance evaluations. Process variables, i.e., chemical composition, current density, frequency, and duty cycle, were considered as inputs; and the corrosion resistance (measured by electrochemical impedance spectroscopy technique) as output data. According to the simulation results in the training stage, a high correlation coefficient was achieved between predicted and measured values (~ 0.99). Using this well-trained ANN model, the proposed ANN model could predict corrosion resistance with a mean square error of approximately 0.0085 made from the test dataset. Examination of the surface morphology suggested a correlation between the microstructure and corrosion performance. The results showed that samples coated at lower Na3PO4, frequency, duty cycle, and higher KF and current density have the highest corrosion resistance. [ABSTRACT FROM AUTHOR]

Commercial pure titanium discs were subjected to sandblasting using varied treatment jet angles, and the samples were subsequently modified by plasma electrolytic oxidation to optimize both mechanical and electrochemical modifications. The coating morphology, real-time images, chemical composition, thickness, microhardness, roughness, and electrochemical behavior were characterized and investigated to research the microstructures and properties comprehensively. Research results demonstrate that an optimal jet angle in sandblasting led to improvements in coating topography, phases, and deposition, contributing to enhanced surface mechanical and anticorrosion performances. The further enhancement of the titania coating properties was attributed to the optimized hybrid electrochemical-mechanical-treatment. [ABSTRACT FROM AUTHOR]

In chemical industrial process, conversion of alkenes to functional oxygenates plays a key role in bridging between the feedstock and downstream application. Traditionally, the oxidation required highly‐active oxygen sources or molecular oxygen under high temperature and pressure. This poses challenges to the green and safe production of oxygenates. To circumvent the issues of massive consumption of fossil fuel and serious CO2 footprints, approaches of electro‐oxidation are developed under ambient conditions, adopting O2 and H2O as oxygen source. Utilizing electricity from renewable resources and the involved electron transfer, the performance is closely related to the interface characteristics of electrodes and electrolytes. This review presents the progress in catalysts design, electrolytes optimization, cells integration to effectively regulate the microenvironment of the interfaces. Further discussion of the mechanism analysis and potential issues are emphasized, based on the in‐situ characterization techniques, isotopic experiments and quenching tests. We hope this review can provide an outline for green approaches to oxidation of alkenes via electrocatalytic pathways. [ABSTRACT FROM AUTHOR]

The widespread application of electrochemical hydrogen production faces significant challenges, primarily attributed to the high overpotential of the oxygen evolution reaction (OER) in conventional water electrolysis. To address this issue, an effective strategy involves substituting OER with the value‐added oxidation of biomass feedstock, reducing the energy requirements for electrochemical hydrogen production while simultaneously upgrading the biomass. Herein, we introduce an electrocatalytic approach for the value‐added oxidation of isobutanol, a high energy density bio‐fuel, coupled with hydrogen production. This approach offers a sustainable route to produce the valuable fine chemical isobutyric acid under mild condition. The electrodeposited Ni(OH)2 electrocatalyst exhibits exceptional electrocatalytic activity and durability for the electro‐oxidation of isobutanol, achieving an impressive faradaic efficiency of up to 92.4 % for isobutyric acid at 1.45 V vs. RHE. Mechanistic insights reveal that side reactions predominantly stem from the oxidative C−C cleavage of isobutyraldehyde intermediate, forming by‐products including formic acid and acetone. Furthermore, we demonstrate the electro‐oxidation of isobutanol coupled with hydrogen production in a two‐electrode undivided cell, notably reducing the electrolysis voltage by approximately 180 mV at 40 mA cm−2. Overall, this work represents a significant step towards improving the cost‐effectiveness of hydrogen production and advancing the conversion of bio‐fuels. [ABSTRACT FROM AUTHOR]

Due to the need to develop methods that optimize the surface properties of lightweight alloys such as aluminum, titanium, and magnesium and align with contemporary requirements of the 21st century, such as enhanced environmental and sanitary efficiency, the plasma electrolytic oxidation (PEO) process stands out as a comprehensive solution. This process can develop oxide coatings on the mentioned alloys, which exhibit superior physical and chemical properties compared with conventional methods. Since 2010, research in this area has been conducted with real-world applications. Recent studies have adopted experimental design approaches to optimize parameters to reduce operational costs and make the technology more accessible. The present study conducted a comparative analysis between treatments performed by conventional methods and by plasma processes, highlighting the most promising results. [ABSTRACT FROM AUTHOR]

• Modification of PEO coatings on Mg alloys by LDH offers a promising avenue for enhancing the protective properties of these materials. • Integration of LDH layers or nanoparticles into PEO coatings has demonstrated significant improvements in corrosion resistance. • Incorporation of LDH layers into PEO coatings significantly enhances their antibacterial and photocatalytic properties. There is an increasing interest in the development of Mg alloys, both for industrial and biomedical applications, due to their favorable characteristics such as being lightweight and robust. However, the inadequate corrosion resistance and lack of antibacterial properties pose significant challenges in the industrial and biomedical applications, necessitating the implementation of advanced coating engineering techniques. Plasma electrolytic oxidation (PEO) has emerged as a preferred coating technique because of its distinctive properties and successful surface modification results. However, there is a continuous need for further enhancements to optimize the performance and functionalities of protective surface treatments. The integration of layered double hydroxide (LDH) into PEO coatings on Mg alloys presents a promising approach to bolstering protective properties. This thorough review delves into the latest developments in integrating LDH into PEO coatings for corrosion-related purposes. It particularly emphasizes the significant improvements in corrosion resistance, antibacterial effectiveness, and photocatalytic performance resulting from the incorporation of LDH into PEO coatings. The two key mechanisms that enhance the corrosion resistance of PEO coatings containing LDH are the anion exchangeability of the LDH structure and the pore-sealing effect. Moreover, the antibacterial activity of PEO coatings with LDH stemmed from the release of antibacterial agents stored within the LDH structure, alterations in pH levels, and the photothermal conversion property. Furthermore, by incorporating LDH into PEO coatings, new opportunities emerge for tackling environmental issues through boosted photocatalytic properties, especially in the realm of pollutant degradation. [Display omitted] [ABSTRACT FROM AUTHOR]

• PEO coating on dissimilar Ti/Mg0.6Ca couple efficiently prevented the galvanic corrosion. • Synchrotron X-ray CT scanning achieved 3D reconstruction of the coating morphology. • CT scanning can be a fast method to assess the corrosion resistance of the coating. With the growing demand for weight reduction, the application of joint lightweight structural materials is increasing. Magnesium alloys feature low density, high specific strength and good formability, offering significant advantages for fuel efficiency and load capacity. Combined with Ti, a dissimilar Ti/Mg composite material provides great flexibility combining the properties of each material. However, because of the great differences in chemical and electrochemical properties between Mg and Ti, it is imperative to address the galvanic corrosion problem of such dissimilar Ti/Mg components. This work presents an investigation of the PEO processing of sintered Ti/Mg0.6Ca couples, aiming to improve the corrosion resistance of such dissimilar alloy combinations using a phosphate-aluminate electrolyte. The results show that uniform and continuous coatings can be formed on the dissimilar Ti/Mg0.6Ca couple. The coating mainly contains MgO and MgAl 2 O 4 on the Mg0.6Ca side, and Al 2 TiO 5 is the dominant phase on the Ti side. The work also took advantage of synchrotron X-ray computed tomography (CT) scanning to achieve 3D reconstruction of the coating morphology, which can be a fast method to assess the porosity and compactness of the coating and further predict the coating corrosion resistance. The coating effectively improved the corrosion resistance of the dissimilar Ti/Mg0.6Ca couple. [Display omitted] [ABSTRACT FROM AUTHOR]