Search Results (158)

The anodization of Ti° enables the formation of well-ordered TiO₂ nanotubes, a highly promising nanomaterial with exceptional photochemical properties and potential applications in the energy and environmental sectors. This study addresses the growth of TiO₂ nanotubes on large-scale surfaces applied for photocatalytic processes. The present investigation approaches the scaling up of the reactor for anodizing Ti°-coated flat surfaces and thus connecting the TiO₂-nano-structure with real-world applications. For this, 316 stainless steel sheets were coated with a uniform Ti° layer using the arc cathodic method. The results indicate that the (~3 µm) thick Ti° arc-PVD coatings are well anodized, despite the inherent amount of µm-sized droplets produced during the deposition. The results reported here highlight the effects of the anodization process parameters—voltage, current, and time—on nanotube growth. At 60 V, the nanotubes exhibited a highly uniform cylindrical morphology, homogeneous walls contributing to an ordered, stable, and open nanostructure at large Ti-coated surfaces. The scaling up of the reactor for the controlled anodization process of Ti° coating is addressed. This approach validates Ti°-based PVD coatings at a semi-industrial scale on commercial stainless steel, thus enabling affordable production costs. Lastly, the anodization of Ti° coatings is a viable, scalable manufacturing process for producing photocatalytic nanostructured surfaces. Full article

This article investigates the anticorrosive properties of Zr-ZrN coatings, including Zr-(Zr,Hf)N, Zr-(Zr,Ti)N, Zr,Hf-(Zr,Hf,Nb)N, and Zr,Nb-(Zr,Nb)N, deposited on AISI 321 stainless steel substrates. The hardness and elasticity modulus of these coatings, as well as their scratch test strength, were measured. Corrosion current densities were calculated using the polarisation resistance method and by extrapolating the linear sections of the cathodic and anodic curves under electrode polarisation. The structure and composition of the sample surfaces were analysed by transmission electron microscopy. Notably, the nitride coatings reduced the corrosion current density in a 3% aqueous NaCl solution at 25 °C by more than 10 times, from 6.96 for the uncoated substrate to 0.17 μA/cm² for the Zr-(Zr,Ti)N-coated sample. The addition of Ti nitride to Zr-ZrN led to the most significant decrease in the corrosion current density. However, the introduction of Nb caused an increase in the corrosion rate and a decrease in the polarisation resistance, and Hf did not affect the corrosion-protective properties of the studied nitride coatings. Full article

Conventional two-dimensional (2D) electrocatalytic ozonation faces challenges such as low mass transfer efficiency, limited hydroxyl radical (•OH) yield, and insufficient pollutant degradation rates. To address these limitations, this study developed a novel three-dimensional electrocatalytic ozonation system using a 316 stainless-steel skeleton as the cathode. By systematically comparing the ozone decay kinetics, •OH yield, imidacloprid degradation efficiency, and ozone mass transfer characteristics among the 3D electrocatalytic ozonation system, 2D electrocatalytic ozonation system, and conventional ozonation system, combined with electrode interface reaction analysis and structural simulation, the core mechanism by which the 3D structure enhances the electrocatalytic ozonation reaction was revealed. The results showed that the 3D electrocatalytic ozonation technology primarily promotes ozone decay and •OH generation through a reaction pathway dominated by the reduction of ozone at the cathode, while simultaneously enhancing pollutant removal efficiency. The pseudo-first-order kinetic constant for ozone decay in the 3D system reached 1.0 min⁻¹, which was five times that of the 2D system (0.2 min⁻¹). The •OH yield increased to 38%, significantly higher than that of the 2D system (15%) and conventional ozonation (10%). The complete degradation of imidacloprid was achieved within 5 min, and the degradation rate (2.14 min⁻¹) was 10 times that of the 2D system. The high specific surface area (75 cm²/g, 30–90 times that of the 2D flat electrode) and 70% porosity of the 3D framework overcame the mass transfer limitation of the 2D structure, exhibiting excellent reaction activity. The ozone mass transfer amount was approximately 1.5 times that of the 2D electrode and 2 times that of conventional ozonation. This study provides theoretical support and technical basis for the engineering application of 3D electrocatalytic ozonation technology in the field of micro-pollutant control. Full article

Microbial electrolysis cells (MECs) present a viable platform for sustainable hydrogen generation from organic waste, but their scalability is limited by cathode performance, cost, and durability. This study evaluates three hybrid carbon nanotube (CNT) cathodes—acid-washed CNT (AW-CNT), thin layer non-acid-washed CNT (TN-NAW-CNT), and thick layer non-acid-washed CNT (TK-NAW-CNT)—each composed of stainless-steel-supported CNTs coated with molybdenum phosphide (MoP). These were benchmarked against woven carbon cloth (WCC) under varied operational conditions. A custom multi-channel reactor operated for 341 days, testing cathode performance across applied voltages (0.7–1.2 V), buffer types (phosphate vs. bicarbonate), pH (7.0 and 8.5), buffer concentrations (10–200 mM), and substrates including acetate, lactate, and treated acid whey. CNT-based cathodes consistently showed higher current densities than WCC across most conditions with significant difference found at higher applied voltages. TK-NAW-CNT achieved peak current densities of 259 A m⁻² at 1.2 V and maintained >41 A m⁻² in real-waste conditions with no added buffer. Long-term performance losses were minimal: 4.5% (TN-NAW-CNT), 0.1% (TK-NAW-CNT), 10.8% (AW-CNT), and 6.8% (WCC). CNT cathodes showed improved performance from reduced resistance and greater electrochemical stability, while proton transfer improvements benefited all materials due to buffer type and pH conditions. These results highlight CNT-based cathodes as promising, scalable alternatives to WCC for energy-positive wastewater treatment. Full article

Diamond-like carbon (DLC) films are valued for their high hardness and wear resistance, but their application in harsh environments is limited by high internal stress and poor corrosion resistance. Co-doping with transition metals offers a promising route to overcome these drawbacks by tailoring microstructure and enhancing multifunctional performance. However, the synergistic effects of Ni and Cr co-doping in DLC remain underexplored. In this study, Ni and Cr co-doped DLC (NiCr-DLC) films were fabricated using filtered cathodic vacuum arc deposition (FCVAD). By varying the C₂H₂ flow rate, the carbon content and microstructure evolved from columnar to fine-grained and compact structures. The optimized film (F55) achieved an ultralow surface roughness (Sa = 0.26 nm), even smoother than the Si substrate. The Ni–Cr co-doping promoted a nanocomposite structure, yielding a maximum hardness of 15.56 GPa and excellent wear resistance (wear rate: 4.45 × 10⁻⁷ mm³/N·m). Electrochemical tests revealed significantly improved corrosion resistance compared to AISI 304L stainless steel, with F55 exhibiting the highest corrosion potential, the lowest current density, and the largest impedance modulus. This work demonstrates that Ni-Cr co-doping effectively enhances the mechanical and corrosion properties of DLC films while improving surface quality, providing a viable strategy for developing robust, multifunctional protective coatings for demanding applications in aerospace, automotive, and biomedical systems. Full article

During the homogenization process of lithium battery slurry, the slurry shearing process causes the surface of the homogenization equipment to wear and generate metal containing debris, which poses a risk of inducing battery self-discharge and even explosion. Therefore, inhibiting wear of homogenizing equipment is imperative, and systematic investigation into the wear behavior and underlying mechanisms of SUS304 stainless steel during homogenization is urgently required. In this study, lithium iron phosphate (LFP) and lithium nickel cobalt manganese oxide (NCM) cathode slurries were used as research objects. Changes in surface parameters, microstructure, and elemental composition of the wear region on SUS304 stainless steel under different working conditions were characterized. The results indicate that in the SUS304-lithium-ion battery slurry system, the potential wear mechanism of SUS304 gradually evolves with changes in load and rotational speed, following the order: adhesive wear (low speed, low load) → abrasive wear (medium speed, high load) → fatigue wear (high speed). Under high-load and high-rotational-speed conditions, oxidative corrosion wear on the ball–disc contact surface is particularly pronounced. Additionally, wear of SUS304 is more severe in the LFP slurry system compared to the NCM system. Macroscopic experiments also revealed that the speed effect is a core factor influencing the wear of SUS304, and the increase in its wear rate is more than twice that caused by the load effect. This study helps to clarify the wear behavior and wear mechanism evolution of homogenization equipment during the lithium battery homogenization process, providing data support and optimization direction for subsequent material screening and surface strengthening treatment of homogenization equipment components. Full article

Phosphorus (P) discharge from onsite wastewater treatment systems (OWTSs) poses a significant threat to water quality, contributing to eutrophication in nutrient-sensitive aquatic environments. In treated effluents, P predominantly exists as orthophosphate (PO₄³⁻), a highly bioavailable and reactive form that requires targeted removal. This study evaluates the performance of electrocoagulation (EC) as a polishing step for PO₄³⁻ removal from OWTS effluents using 12 anode/cathode combinations comprising aluminum (Al), iron (Fe), magnesium (Mg), and stainless steel (SS). Key operational parameters, including treatment time, mixing speed, current density, pH, and initial PO₄³⁻ concentration, were systematically investigated when synthetic denitrified effluent (20 mg P/L) was treated. Based on the performance, the four most effective electrode combinations (Al/Al, Al/Mg, Fe/Al, and Mg/Mg), along with a commercial benchmark (Fe/Fe), were further tested under extended hydraulic retention times (up to 48 h) in both synthetic and real (denitrified) wastewater. To date, none of the studies have systematically evaluated all possible anode/cathode combinations involving multiple electrode materials under uniform operational conditions. The Al/Al and Mg/Mg EC systems achieved rapid and high PO₄³⁻ removal efficiencies (>95%), while Mg-based systems demonstrated sustained performance over prolonged treatment durations, especially in real wastewater. Bimetallic pairs such as Al/Mg and Fe/Al exhibited synergistic effects through enhanced coagulant generation and pH stabilization. The results indicated that PO₄³⁻ removal efficiency was strongly influenced by electrode material selection, hydrodynamic conditions, and wastewater compositions, underscoring the need to design EC systems based on site-specific water quality conditions in OWTSs. Full article

This study assesses how different anode materials influence neutron production rates (NPRs) in multi-state fusion (MSF) reactors, with a particular focus on the effects of deuterium (D) pre-loading on the anode surface. Three types of mesh anodes were assessed: stainless steel (SS), zirconium (Zr), and D pre-loaded zirconium (ZrD). MSF operates using two electrodes to confine ions to various fusion reactions, including D-D and D-T. The reactor features a negatively biased central cathode and a grounded anode within a vacuum vessel. Neutrons and protons are produced through the application of high voltage (tens of kV) and current (tens of mA) on the system to spark the plasma and start the fusion. Assessments at voltages up to 50 kV and currents up to 30 mA showed that Zr mesh anodes produced higher NPRs than SS ones, reaching 1.912 at 30 kV. This increased performance is attributed to surface fusion processes occurring in the anode. These processes were further modified by the deuterium pre-loading in the ZrD anode, as compared to SS and Zr with 1.832 at 30 kV. The findings suggest that material properties and deuterium pre-loading play significant roles in optimizing the efficiency of MSF reactors and the NPR. Future research may explore the long-term stability and durability of these anode materials under continuous operation conditions to fully harness their potential in fusion energy applications. Full article

The electrooxidation (EO) of three important environmental contaminants, anticorrosive 1H-benzotriazole (BTA), plasticizer dibutyl phthalate (DBP), and non-ionic surfactant Triton X-100 (tert-octylphenoxy[poly(ethoxy)] ethanol, t-OPPE), was studied as a possible means to improve their elimination from wastewaters, which are an important emission source. EO was performed in a batch reactor with a boron-doped diamond (BDD) anode and a stainless steel cathode. Different supporting electrolytes were tested: NaCl, H₂SO₄, and Na₂SO₄. Results were analysed from the point of their efficacy in terms of degradation rate, kinetics, energy consumption, and transformation products. The highest degradation rate, shortest half-life, and lowest energy consumption was observed in the electrolyte H₂SO₄, followed by Na₂SO₄ with only slightly less favourable characteristics. In both cases, degradation was probably due to the formation of persulphate or sulphate radicals. Transformation products (TPs) were studied mainly in the sulphate media and several oxidation products were identified with all three contaminants, while some evidence of progressive degradation, e.g., ring-opening products, was observed only with t-OPPE. The possible reasons for the lack of further degradation in BTA and DBP are too short of an EO treatment time and perhaps a lack of detection due to unsuitable analytical methods for more polar TPs. Results demonstrate that BDD-based EO is a robust method for the efficient removal of structurally diverse organic contaminants, making it a promising candidate for advanced water treatment technologies. Full article

Stainless steel (SS) is one of the materials most commonly utilized for fabrication of medical implants and its properties are often improved by deposition of protective coatings. This study investigates certain physico-chemical and biological properties of SS substrate coated with multilayer thin film consisting of titanium nitride and silver layers (TiN-Ag film). TiN-Ag films were deposited on the surface of AISI 316 SS substrate by a combination of cathodic arc evaporation and DC magnetron sputtering. SS substrate was analyzed by TEM, while deposited coatings were analyzed by SEM, EDS and wettability measurements. Also, mitochondrial activity assay, and osteogenic and chondrogenic differentiation were performed on dental pulp stem cells (DPSCs). SEM and EDS revealed excellent adhesion between coatings’ layers, with the top layer predominantly composed of Ag, which is responsible for antibacterial properties. TiN-Ag film exhibited moderately hydrophilic behaviour which is desirable for orthopedic implant applications. Biological assays revealed significantly higher mitochondrial activity and enhanced osteogenic and chondrogenic differentiation of DPSC on TiN-Ag films compared to TiN films. The newly designed TiN-Ag coatings showed a great potential for the surface modification of SS implants, and further detailed investigations will explore their suitability for application in clinical practice. Full article

Electrocoagulation is rapidly gaining prominence in wastewater treatment due to its capabilities and less reliance on additional chemicals. While a lot of research efforts have been focused on the influence of the anode material, power supply, and reactor design, the contribution of the cathode to contaminant removal has been less explored. In this study, we investigated the performance of stainless steel (SS-304) and aluminium (Al-6061) electrodes in both similar and dissimilar configurations for a 120 min electrocoagulation treatment of spent machinery coolant. The anode–cathode configurations, including SS-SS, Al-Al, SS-Al and Al-SS, have been investigated. Additionally, we examined the effects of the initial pH and agitation methods on the process performance. Our findings indicated that the type of cathode could significantly affect the floc formation and contaminant removal. Notably, the combination of an Al anode and SS cathode (Al(A)-SS(C)) demonstrated a synergistic improvement in the Chemical Oxygen Demand (COD), with a removal of 84.3% within a short treatment time (<20 min). The final COD removal of 91.4% was achieved with a turbidity level close to 12 Nephelometric Turbidity Units (NTU). The Al anode readily released the Al ions and formed light flocs at the early stage of electrocoagulation, while the SS cathode generated heavy Fe hydroxides that mitigated the flotation effect. These results demonstrated the cathode’s significant contribution in electrocoagulation, leading to potential savings in the treatment time required. Full article

This study focuses on the design and optimization of a monopolar electrode configuration for the hybrid electrochemical treatment of real washing machine wastewater. A combined electrocoagulation (EC) and electro-oxidation (EO) system was optimized to maximize pollutant removal efficiency while minimizing energy consumption. The monopolar setup employed mixed metal oxide (MMO) and aluminum anodes, along with a stainless steel cathode, operating under controlled conditions with sodium chloride as the supporting electrolyte. An applied current density of 15 mA cm⁻² achieved 90% chemical oxygen demand (COD) removal, 98% surfactant degradation, complete turbidity reduction within 120 min, and pH stabilization near 8. Additionally, electrochemical disinfection achieved <2 MPN/100 mL, with no detectable phenols and the presence of organic anions such as oxalate and acetate. These results demonstrate the effectiveness of an optimized monopolar EC–EO system as a cost-efficient and sustainable strategy for wastewater treatment and potential water reuse. Further studies should focus on refining energy consumption and monitoring reaction by-products to enhance large-scale applicability. Full article

This study investigates the tensile behaviors of wrought 44W steel, Monel 400, 304L austenitic stainless steel, and arc-directed energy deposited (arc-DED) 308L austenitic stainless steel under simulated hydrogen environments to evaluate their endurance to hydrogen embrittlement (HE). The specimens were subjected to cathodic hydrogen charging in an alkaline solution, followed by uniaxial tensile testing at a strain rate of 0.2 min⁻¹. Based on measurements of elongation and toughness, the resistance to HE was ranked as follows: 304L stainless steel > Monel 400 > arc-DED 308L stainless steel > 44W steel. Notably, no significant changes were observed in the yield strengths, ultimate tensile strengths, or elastic modulus of 304L austenitic stainless steel, Monel 400, and 44W steel across all the levels of hydrogenation. However, the arc-DED 308L stainless steel exhibited a slight increase in these properties, attributed to its unique microstructural characteristics and strengthening mechanisms inherent to additive manufacturing processes. These outcomes contribute to a better understanding of the mechanical performance and suitability of these structural alloys in hydrogen-rich environments, highlighting the superior HE resistance of 304L stainless steel and Monel 400 for such applications. Full article

Ti/a-C:Cr multilayer films were deposited on 316L stainless steel (SS316L) substrates using medium-frequency alternating current magnetron sputtering, with a single-layer a-C:Cr film also prepared on a titanium substrate. The influence of sputtering pressure on the film’s structure and properties was systematically investigated. Film morphology and microstructure were analyzed via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). At a pressure of 1.4 MPa, the interfacial contact resistance (ICR) of SS316L bipolar plates (BPPs) coated with the films reached as low as 3.30 mΩ·cm², while that of titanium BPPs was 2.90 mΩ·cm². Under simulated proton exchange membrane fuel cell (PEMFC) cathode conditions (70 °C, 0.6 V vs. SCE, 0.5 M H₂SO₄, 5 ppm HF solution), the corrosion current density, Icorr, reached optimal values of 0.69 μA·cm⁻² for SS316L and 0.62 μA·cm⁻² for titanium. These results demonstrate that parameter optimization enables SS316L BPPs to functionally replace titanium counterparts, offering significant cost reductions for metal BPPs and accelerating the commercialization of PEMFC technology. Full article

The primary challenge associated with stainless steel in fuel cell operation is its susceptibility to corrosion, which leads to increased contact resistance and subsequent degradation of electrochemical performance. In general, the protective layers have been loaded onto the metal surface by widely used traditional techniques such as physical vapor deposition (PVD), or cathode arc ion plating. However, the above sputtering and evaporation ways require a high-vacuum condition, complicated experimental setups, higher costs, and an elevated temperature. Therefore, herein the achievement for uniform coatings over a large surface area has been realized by using a cost-effective strategy through a complete wet chemical process. The synergistic regulation of two conductive components and a plastic additive has been employed together with the entrapment of a surfactant to optimize the microstructure of the coating surface. The assembly of layered graphite and a polystyrene sphere could maintain both the high corrosion resistance feature and excellent electrical conductivity. In particular, the intrinsic vacant space in the above physical barriers has been filled with fine powders of indium tin oxide (ITO) due to its small size, and the interconnected conductive network with vertical/horizontal directions would be formed. All the key technical targets based on the U.S. Department of Energy (DOE) have been achieved under the simulated operating environments of a proton exchange membrane fuel cell. The corrosion current density has been measured as low as 0.52 μA/cm² (for the sample of graphite/mixed layer) over the applied potentials from −0.6 V to 1.2 V and its protective efficiency is evaluated to be 99.8%. The interfacial contact resistance between the sample and the carbon paper is much less than 10 mΩ·cm² (3.4 mΩ·cm²) under a contact pressure of 165 N/cm². The wettability has been investigated and its contact angle has been evolved from 48° (uncoated sample) to even 110°, providing superior hydrophobicity to prevent water penetration. Such an innovative approach opens up new possibilities for improving the durability and reducing the costs of carbon-based coatings. Full article