Anodic Oxidation Research Articles

Rare earth oxides nanoparticles formed on the surface of WE43 magnesium alloy subjected to anodic oxidation plus heat treatment for anti-bone tumor

It was well known that rare earth elements (REE) oxides nanoparticles could inhibit tumor growth and promote osteogenesis. In this works, four WE43 magnesium alloys (AO-10, AO-30, AO-1h and AO-2h) containing different REE oxides nanoparticles were prepared by anodic oxidation plus heat treatment. The REE oxides nanoparticles on AO-10, AO-30, AO-1h and AO-2h surface were Gd2O3 and Nd2O3, (Gd0.745Y1.255)O3 and Nd2O3, (Gd0.18Y1.82)O3 and Gd2O3 as well as Y2O3 and Gd2O3, respectively. Subsequently, the bioactivity, antitumor property and osteogenic property of all materials in vitro and in vivo were studied, and their antitumor property, bioactivity and osteogenic property were all AO-2h > AO-1h > AO-30 > AO-10. The degradation behaviors of materials in vitro and vivo were further investigated, and the corrosion resistance of materials was AO-10 > AO-30 > AO-1h > AO-2h. AO-2h released the most H2 and produced the highest pH value in all materials during degradation. The results showed that the effects of different REE oxides nanoparticles on corrosion resistance, biactivity, osteogenic property and antitumor property of materials were different completely. In all materials, AO-30 had moderate inhibition of MG63 and 143B cells in vitro, and it could inhibit the growth of bone tumor in mice in vivo. Then, the osteogenic property of AO-30 was moderate. It could promote the adhesion and proliferation of MC3T3-E1 cells. Again, the corrosion resistance of AO-30 was relatively excellent. It release few H2, Mg2+ and REE. The REE levels in normal tissues were relatively low, whose effects was negligible. Hence, AO-30 was the most suitable material for anti-bone tumor in all materials.

An innovative combination of anodic oxidation using Cu/SnO2–Sb2O5 rotating cylinder anode with TiO2 photocatalytic process for treating hospital wastewater

Treatment of hospital wastewater was achieved successfully using a novel combined process composed of an anodic oxidation with Cu/SnO2–Sb2O5 rotating cylinder anode and a photocatalysis process with titanium oxide nanoparticles. Cu/SnO2–Sb2O5 anode and TiO2 nanoparticles were characterized by x-ray diffractometer (XRD) and scanning electron microscopy (SEM). The feasibility of the combined process was evaluated using response surface methodology (RSM). Three operating factors were studied namely current density (10–20 mA/cm2), pH (4–8), and TiO2 dosage (0.3–0.7 g/L). Results showed that current density has the major effect on the COD removal with a contribution percent of 40 %. The optimal conditions were current density of 20 mA/cm2, pH of 4, and TiO2 dosage of 0.7 g/L in which COD removal of 91.2 % was achieved with claiming a total electrical energy (EECT) of 39.41 kWh/ m3. An interesting synergistic effect with a synergy of 21.26 % was recognized in the combined process due to the high productivity of hydroxyl radicals resulting from the interaction between the individual processes. Results confirmed that coupling anodic oxidation with photoctalysis is a promising method for treating hospital wastewater.

Illuminating Biomimetic Nanochannels: Unveiling Macroscopic Anticounterfeiting and Photoswitchable Ion Conductivity via Polymer Tailoring.

Artificial photomodulated channels represent a significant advancement toward practical photogated systems because of their remote noncontact stimulation. Ion transport behaviors in artificial photomodulated channels, however, still require further investigation, especially in multiple nanochannels that closely resemble biological structures. Herein, we present the design and development of photoswitchable ion nanochannels inspired by natural channelrhodopsins (ChRs), utilizing photoresponsive polymers grafted anodic aluminum oxide (AAO) membranes. Our approach integrates spiropyran (SP) as photoresponsive molecules into nanochannels through surface-initiated atom transfer radical polymerization (SI-ATRP), creating a responsive system that modulates ionic conductivity and hydrophilicity in response to light stimuli. A key design feature is the reversible ring-opening photoisomerization of spiropyran groups under UV irradiation. This transformation, observable at the molecular level and macroscopically, allows the surface inside the nanochannels to switch between hydrophobic and hydrophilic states, thus efficiently modulating ion transport via changing water wetting behaviors. The patternable and erasable polySP-grafted AAO, based on a controllable and reversible photochromic effect, also shows potential applications in anticounterfeiting. This study pioneers achieving macroscopic anticounterfeiting and photoinduced photoswitching through reversible surface chemistry and expands the application of polymer-grafted structures in multiple nanochannels.

Introducing oxygen vacancies into WO3 thin film for improving hydrogen sensing performance of Pd/WO3-x/AAO sensors

Introducing oxygen vacancy into semiconducting metal oxides (SMOs) is a strategic approach to promote their gas sensing performances. In this paper, the WO3-x thin films were meticulously deposited onto an anodic aluminum oxide (AAO) substrate, and the oxygen vacancies concentrations of WO3-x thin films were changed by adjusting the ratio of flux of Ar to O2 in magnetron sputtering process. Sequentially, a layer of palladium (Pd) was deposited on the WO3-x/AAO films, creating a nano-mesh structured hydrogen sensor with Pd as the catalytic element. The resulted amorphous WO3-x samples with varying concentration of oxygen vacancies were thoroughly analyzed using XPS and ESR, which confirmed that the oxygen vacancies concentration escalated with an increase in the ratio of flux of Ar to O2. The hydrogen sensitivity of prepared Pd/WO3-x/AAO sensors were examined. Our findings revealed an enhancement in hydrogen sensitivity for the sensors with an optimal concentration of oxygen vacancies. However, an excess of these vacancies was found to deteriorate their hydrogen sensing performance. Notably, the optimized Pd/WO3-x/AAO sensor exhibited a marked response even at a hydrogen concentration as low as 100 ppb, demonstrating its high sensitivity and selectivity towards hydrogen detection.

Polarized and Directional Electroluminescence from Organic Light‐Emitting Devices by Using a Bifunctional Meta‐Electrode

AbstractOrganic light‐emitting devices (OLEDs) with polarized and directional emission are highly desired for their promising applications in optical imaging, optical communication, and immersive visual technologies. Existing implementation methods based on free space bulk optical elements suffer from significant power loss, limiting their practical applications. Here, a bifunctional meta‐electrode is proposed by integrating a metasurface consisting of Ag periodic corrugations onto the indium tin oxide (ITO) anode to simultaneously realize the functions of charge carrier injection and photon management in the OLEDs. Highly polarized and directional light emission is demonstrated while maintaining a high device efficiency using the meta‐electrode. The electroluminescence with a polarization extinction ratio of 5 is achieved by judiciously engineering the polarization‐dependent Purcell factor of the resonant cavity constructed by the meta‐electrode. Meanwhile, the directional light emission with a divergence angle of 10° can be obtained by the efficient out‐coupling of surface plasmon‐polariton mode. The light beam can be collimated in one direction by using 1D nanogratings and in two directions by using 2D nanopillars, respectively.

Formation and reactivity of electrogenerated lewis acids by oxidation of Bu4NB(C6F5)4 under weakly coordinating conditions

This study explores the generation and application of electrogenerated Lewis acids (EGLA) through anodic oxidation of tetrakis(pentafluorophenyl)borate, B(C6F5)4−, in weakly coordinating electrolytes. Employing Bu4NB(C6F5)4/CH2Cl2 as the electrolyte, bis(perfluorophenyl)borane (PFB), a highly reactive Lewis acid, was generated and utilized in various organic transformations. Cyclic voltammetry confirmed the onset of oxidation at 1.8 V vs. Ag/AgNO3, which led to the formation of the EGLA species. The EGLA system was successfully applied for the defluorination of 1-fluoroadamantane and other alkyl fluorides in both batch and flow electrolysis systems. Additionally, EGLA was effective in catalyzing diverse reactions, including Friedel-Crafts dimerization, deoxygenation of triphenylmethanol, and carbonyl–olefin metathesis, outperforming traditional Lewis acids, such as PFB and tris(pentafluorophenyl)borane. The reactivity of EGLA is strongly dependent on the solvent environment, with weakly coordinating solvents being critical for maintaining activity. This study highlights the potential of EGLA as a versatile and highly active catalyst for a broad range of organic transformations, emphasizing the importance of solvent selection in maximizing its reactivity.

Bimetal Metaphosphate/Molybdenum Oxide Heterostructure Nanowires for Boosting Overall Freshwater/Seawater Splitting at High Current Densities.

Exploring excellent non-noble bifunctional electrocatalysts for freshwater/seawater splitting at high current densities has attracted extensive interest owing to strong anodic oxidation and severe chloride corrosion challenges. Herein, hierarchical bimetal Ni-Co metaphosphate/molybdenum oxide heterostructure nanowires (NiCoMoPO) are rationally designed and fabricated to efficiently boost oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline freshwater/seawater, where the favorable electronic structure from heterostructures, signified by X-ray absorption spectra, endows NiCoMoPO with the enhanced intrinsic activity, while its hierarchical nanowire structure and heterostructures provide abundant active sites. Additionally, the PO3 - improves the chloride-corrosion resistance and efficiently facilitates the OER kinetics verified by theoretical and experimental studies. Therefore, NiCoMoPO drives 1000mA cm-2 at low overpotentials of 467 and 442mV for OER and HER in alkaline freshwater respectively, as well as a small cell voltage of 2.135V for overall freshwater splitting with robust durability of 300h. Impressively, due to the strong corrosion resistance, at 500mA cm-2 of overall seawater splitting, NiCoMoPO maintains almost 2.096V for 1200h, indicating promising practical applications. This work sheds light on the rational design and fabrication of outstanding electrocatalysts at high current densities of seawater/freshwater splitting.

Promoting nitrogen-doped porous phosphorus spheres for high-rate lithium storage

Phosphorus anode has shown great potential for the high-rate and high-energy–density lithium-ion batteries. Nevertheless, it still suffers from possible electrode cracking, ion-transport restrictions, and active-particle decomposition resulting from repeated alloying/de-alloying. To address the aforementioned issues, a nitrogen-doped flower-like porous phosphorus (f-P) sphere has been developed. The abundant micro-mesopores facilitate ion diffusion and enhance the internal bonding strength of the electrode. Concurrently, the doped nitrogen promotes the generation of a favorable solid electrolyte interphase constructed by fast-ion-conductors. As a result, the f-P exhibits a high-rate capacity of 735mAh g−1 at 20 A g−1 and maintains high Coulombic efficiencies over 900 cycles at 10 A g−1. Furthermore, coin full-cells comprising the f-P anode and lithium cobalt oxide cathode demonstrate stable operation at a high current density of 6 mA cm−2. The combination of a porous structure and doping strategy represents a viable approach for strengthening the durability of electrodes and optimizing the ion transport kinetics of advanced alloy anode materials.

Study of Thermal Processes in Porous Anodic Aluminum Oxide Filled With Perovskite

Study of Thermal Processes in Porous Anodic Aluminum Oxide Filled With Perovskite

Anodic Dissolution and Electropolishing of Titanium in an Amide-Type Ionic Liquid Containing Halide Ions

Anodic dissolution of titanium was investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)amide (BMPTFSA) in the presence of halide ions, Cl– and Br–. Electropolishing of Ti was possible in the presence of Cl– at 353 K, suggesting that the surface of a Ti electrode with the native oxide layer was activated by Cl–. The dissolved species of Ti after anodic dissolution of Ti at 0 V vs. Ag|Ag(I) was found to be tetravalent [TiCl6]2–, because the applied potential was more positive than the redox potential of [TiCl6]2–/[TiCl6]3–. The morphology of a Ti electrode changed after potentiostatic anodic oxidation at –0.5 V in BMPTFSA containing BMPBr, indicating that anodic dissolution of Ti was possible in the presence of Br–.

Assessing the electrode configuration in a sandbox system for the removal of sulfanilamide: A pilot study

Electrochemical oxidation has emerged as an effective and straightforward technology for groundwater remediation. While recent studies have investigated parameters such as current, electrolyte composition, and electrode materials, most have been conducted using small-scale batch or flow reactors, limiting their applicability to real-world conditions. In this study, a pilot-scale sandbox reactor was employed to simulate realistic groundwater conditions and assess the removal of sulfanilamide, a model organic contaminant. Various electrode configurations were systematically evaluated to identify the key operational parameters influencing pollutant removal efficiency, providing insights for practical applications in groundwater treatment. This study proposes three configurations, including a single well with the anode and cathode, a double well with the separated anode and cathode, and an e-barrier with electrodes separately mounted inside a permeable barrier. Single well had the lowest removal efficiency (60%) because cathodic reaction inhibited the anodic oxidation. A double well with a separate anode and cathode can achieve 80% removal efficiency. However, effluent pH can reach up to 13.2, which can adversely impact groundwater. Meanwhile, the e-barrier not only achieved complete removal, but also maintained a neutral pH of 7.0 over 30 days. The e-barriers proved to be the most effective configuration based on their removal efficiency (100%) while yielding an effluent with neutral pH. The energy consumption of the e-barrier was most effective at 1.54 kWh/m3, while the other configurations were 5.40 and 22.18 kWh/m3. E-barriers are deemed a very reasonable configuration, both in terms of removal efficiency and practical application in groundwater.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

A portable micro-nanochannel bio-3D printed liver microtissue biosensor for DON detection

We investigated a portable micro-nanochannel biosensor 3D-printed liver microtissues for rapid and sensitive deoxynivalenol (DON) detection. The screen-printed carbon electrode (SPCE) was modified with nanoporous anodic aluminum oxide (AAO), gold nanoparticles (AuNPs), and cytochrome C oxidase (COx) to enhance sensor performance. Gelatin methacrylate hydrogel, combined with hepatocellular carcinoma cells, formed the bioink for 3D printing. Liver microtissues were prepared through standardized and high-throughput techniques via bio-3D printing technology. These microtissues were immobilized onto modified electrodes to fabricate liver microtissue sensors. The peak current of this biosensor was positively correlated with DON concentration, as determined by cyclic voltammetry (CV), within a linear detection range of 2∼40 μg/mL. The standard curve equation is denoted by ICV(μA)= =18.76956+0.03107CDON(μg/mL), with a correlation coefficient R2 was 0.99471(n＝3). A minimum detection limit of 1.229 μg/mL was calculated from the formula, indicating the successful construction of a portable micro-nanochannel bio-3D printed liver microtissue biosensor. It provides innovative ideas for developing rapid and convenient instrumentation to detect mycotoxin hazards after grain production. It also holds significant potential for application in the prediction and assessment of post-production quality changes in grain.

Pinhole small-angle neutron scattering based approach for desmearing slit ultra-small-angle neutron scattering data.

Presented here is an effective approach to desmearing slit ultra-small-angle neutron scattering (USANS) data, based on complementary small-angle neutron scattering (SANS) measurements, leading to a seamless merging of these data sets. The study focuses on the methodological aspects of desmearing USANS data, which can then be presented in the conventional manner of SANS, enabling a broader pool of data analysis methods. The key innovation lies in the use of smeared SANS data for extrapolating slit USANS, offering a self-consistent integrand function for desmearing with Lake's iterative method. The proposed approach is validated through experimental data on porous anodized aluminium oxide membranes, showcasing its applicability and benefits. The findings emphasize the importance of accurate desmearing for merging USANS and SANS data in the crossover q region, which is particularly crucial for complex scattering patterns.

NiMnO nanoparticle-activated carbon anodes for efficient urea oxidation and energy production in wastewater-driven direct urea fuel cells

The growing concern over urea-containing wastewater from industrial sources necessitates innovative treatment solutions that also offer sustainable energy production. In this study, a novel anode material is developed by decorating activated carbon with NiMnO nanoparticles through thermal treatment under an inert atmosphere. The resulting NiMnO NPs-decorated activated carbon was evaluated for its electrocatalytic performance in the electrooxidation of urea and its application in a direct urea fuel cell (DUFC). X-ray diffraction patterns confirmed the formation of nickel metal and Mn(II) oxide, with activated carbon showing representative peaks. Scanning electron microscopy images revealed well-dispersed nanoparticles on the activated carbon surface, corroborated by uniform elemental distribution from mapping results. Electrochemical measurements using cyclic voltammetry demonstrated that the 30 wt% MnAc sample exhibited the highest electrocatalytic activity among the tested samples (0, 5, 10, 20, 30, 40 and 50 wt% MnAc) with a maximum current density of 123 mA/cm2 at 3.0 M urea concentration and an onset potential of −0.02 V versus Ag/AgCl. Linear sweep voltammetry of the assembled DUFC showed promising open circuit potentials of 0.82 V and maximum power densities reaching 4.9 W/m2, achieved using industrial wastewater from the Egyptian Chemical Industries Company (KIMA) in Aswan, Egypt. The results highlight the efficacy of NiMnO NPs-decorated activated carbon in both urea oxidation and electrical energy generation. This study not only provides a viable method for treating urea-rich industrial wastewater but also presents a sustainable approach to energy production. The findings underscore the potential of this material for future applications in DUFCs, offering significant environmental and economic benefits.

Recent Progress of Corrosion Prevention Method of Magnesium Alloy

Magnesium (Mg) and its alloys have received much attention in the aerospace, transportation, automotive industry, and military equipment fields due to their unique chemical and physical properties, such as their low density and high specific strength, particularly as the lightest structural metal materials, with the opportunity to achieve the design of lighter engineering systems. With the continuous improvement of processing technology, the application scope of magnesium alloy is rapidly expanding, and market demand is increasing. However, because of its significant electronegativity (2.37 V) and loose naturally formed oxide coating, magnesium has low corrosion resistance in comparison to other structural metal elements, severely limiting its large‐scale use. This review summarizes several typical anticorrosion methods for magnesium alloys, including chemical conversion coating treatment, anodic oxide film treatment, micro‐arc oxidation treatment, laser surface treatment, ion implantation, physical vapor deposition, and superhydrophobic coating. In most cases, the corrosion resistance of magnesium and its alloys has improved, but it has a certain degree of environmental damage. It is hoped that this review will contribute to further developing magnesium alloy materials in the field of preservative coating.

Enhancing Tin Dioxide Anode Performance by Narrowing the Potential Range and Optimizing Electrolytes

Tin dioxide (SnO2) is a low-cost and high-capacity anode material for lithium-ion batteries, but the fast capacity fading significantly limits its practical applications. Current research efforts have focused on preparing sophisticated composite structures or optimizing functional binders, both of which increase material manufacturing costs. Herein, we utilize pristine and commercially available SnO2 nanopowders and enhance their cycling performance by simply narrowing the potential range and optimizing electrolytes. Specifically, a narrower potential range (0–1 V) mitigates the capacity fading associated with the conversion reaction, whereas an ether-based electrolyte further suppresses the volume expansion related to the alloy reaction. Consequently, this SnO2 anode delivers a promising battery performance, with a high capacity of ~650 mAhg−1 and stable cycling for 100 cycles. Our work provides an alternative approach to developing high-capacity and long-cycling metal oxide anode materials.

New Method of Color Anodic Oxide Coating Using Traditional Indigo Dye

New Method of Color Anodic Oxide Coating Using Traditional Indigo Dye

Effect of citrate anion incorporation on dielectric properties of anodic oxide grown on Ti-Si alloy

Effect of citrate anion incorporation on dielectric properties of anodic oxide grown on Ti-Si alloy