Electrochemical Anodization Method Research Articles

The X-Direction Scanning of Atomic Force Microscopy to Analyze Porous Silicon P-Type Si(100) Fabricated by Electrochemical Anodization Method

This work only investigated the x-direction scanning of atomic force microscopy, which can accurately measure porous silicon's width, depth, and roughness. Pores on p-type Si (100) surfaces fabricated by electrochemical anodization method with the variation of resistivity and current density, i.e., 0.001-0.005 Ω.cm (high dopant) and 1-10 Ω.cm (low dopant), and 4, 6, 8, and 10 mA/cm2, respectively. Macroporous silicon was obtained for both high and low dopants. Pore width, pore depth, and roughness of silicon increase with increasing the current density. Characteristics of porous silicon for high dopants are smaller than that for low dopants. It indicates that large amounts of dopant in silicon can slow the etching process.

Synthesis and Characterization of TiO2 Nanotubes for High-Performance Gas Sensor Applications

In this study, we investigated the fabrication, properties, and sensing applications of TiO2 nanotubes. A pure titanium metal sheet was used to demonstrate how titanium dioxide nanotubes can be used for gas-sensing applications through the electrochemical anodization method. Subsequently, X-ray diffraction indicated the crystallization of the titanium dioxide layer. Scanning electron microscopy and transmission electron microscopy then revealed the average diameter of the TiO2 nanotubes to be approximately 100 nm, with tube lengths ranging between 3 and 9 µm and the thickness of the nanotube walls being about 25 nm. This type of TiO2 nanotube was found to be suitable for NO2 gas sensor applications. With an oxidation time of 15 min, its detection of NO2 gas showed a good result at 250 °C, especially when exposed to a NO2 gas flow of 100 ppm, where a maximum NO2 gas response of 96% was obtained. The NO2 sensors based on the TiO2 nanotube arrays all exhibited a high level of stability, good reproducibility, and high sensitivity.

Construction of 0D Ti3C2Tx MXene nanoparticles sensitized 1D TiO2 nanotube arrays for enhanced photocatalytic and photoelectrochemical properties

Developing efficient photocatalysts with highly active facets and appropriate cocatalyst hybridization to form heterostructure is a valid way to expedite the separation of photoexcited electron-hole pairs. Herein, a novel 0D/1D Ti3C2Tx MXene/TiO2 photocatalyst was fabricated for photoelectrochemical (PEC) water splitting and tetracycline antibiotic photocatalytic degradation. Meanwhile, highly-exposed TiO2 nanotube arrays were prepared by electrochemical anodizing method, and Ti3C2Tx nanoparticles with mixed terminal group were uniformly grown on the surface of TiO2 through the hydrothermal and solvothermal process, respectively. Compared with pure TiO2, the Ti3C2Tx/TiO2 heterostructure exhibited different degrees of enhancement in PEC and photocatalytic degradation activities under simulated sunlight. The TNT/M-h sample yielded a photocurrent density of 1.77 mA cm−2 at 0 V (vs. SCE) and achieved a 95.57 % photocatalytic removal rate of tetracycline within 140 min. The excellent performance originated from the strong interfacial contact and work function discrepancy between the ordered tubular structure of TiO2 and 0D Ti3C2Tx nanoparticles, which realized the high-efficiency photogeneration and transfer of electron-hole pairs.

Electrophoretic loading of alendronate on TiO2 nanotube arrays

TiO2 nanotube arrays(TNTs) were prepared on titanium-based surfaces by electrochemical anodic oxidation method and used as drug delivery carriers. Using the principle of electrophoresis, the drug loading capacity of alendronate was significantly increased to achieve a long-term sustained release. Chitosan(CS) coating containing diclofenac sodium(DCS) on the surface of TNTs conferred anti-inflammatory and pH-smart response properties to the materials and improved antimicrobial and osseointegration properties. These findings are important for improving the performance of bone implant materials.

Photocatalytic activities of Fe2O3 coated ZnO nanowires grown by electrochemical anodization method

In this study, the visible light photocatalytic activities of the ZnO and ZnO/Fe2O3 structures were investigated. Anodization of Zn plates to obtain ZnO nanowires was carried out by applying 35 V between 1 and 30 min durations. Fe2O3 layers were coated on initially obtained ZnO nanowires through a sol-gel spin-coating process. All samples were examined for morphological, structural, optical, and photocatalytic activities in detail. The results showed that the conducted anodization process was successful where up to micrometer-length nanowires were obtained. SEM images confirmed the presence of Fe2O3 deposits surrounding the nanowires, while UV and visible absorption spectra indicated increased absorption due to Fe2O3, leading to enhanced photocatalytic performance. The best-performing ZnO nanowire anodized for 5 min almost doubled its photocatalytic activity after Fe2O3 coating, in which an apparent reaction rate of 12.24 × 10−3 min−1 and degrading 90.32 % of the initial MB concentration was recorded.

Various Antibacterial Strategies Utilizing Titanium Dioxide Nanotubes Prepared via Electrochemical Anodization Biofabrication Method.

Currently, titanium and its alloys have emerged as the predominant metallic biomaterials for orthopedic implants. Nonetheless, the relatively high post-operative infection rate (2-5%) exacerbates patient discomfort and imposes significant economic costs on society. Hence, urgent measures are needed to enhance the antibacterial properties of titanium and titanium alloy implants. The titanium dioxide nanotube array (TNTA) is gaining increasing attention due to its topographical and photocatalytic antibacterial properties. Moreover, the pores within TNTA serve as excellent carriers for chemical ion doping and drug loading. The fabrication of TNTA on the surface of titanium and its alloys can be achieved through various methods. Studies have demonstrated that the electrochemical anodization method offers numerous significant advantages, such as simplicity, cost-effectiveness, and controllability. This review presents the development process of the electrochemical anodization method and its applications in synthesizing TNTA. Additionally, this article systematically discusses topographical, chemical, drug delivery, and combined antibacterial strategies. It is widely acknowledged that implants should possess a range of favorable biological characteristics. Clearly, addressing multiple needs with a single antibacterial strategy is challenging. Hence, this review proposes systematic research into combined antibacterial strategies to further mitigate post-operative infection risks and enhance implant success rates in the future.

Enhancing photocatalytic performance of BiOI/TiO2 NTs nanocomposites through SILAR optimization for methylene blue degradation

BiOI nano-leaves were deposited on to TiO2 nanotubes (NTs) using the Successive Ionic Layer Adsorption and Reaction (SILAR) technique, which was developed using the electrochemical anodization method. Various SILAR cycle numbers (three, five, and seven cycles) were employed in the experiment. The as-prepared nanocomposites (NCs) were characterized by several technique, the morphology of the elaborated NCs samples was examined using a S − 4800 field emission scanning electron microscope (SEM), the Reflectance and diffuse reflectivity of the NCs samples were measured by a Shimadzu UV-3100S spectrophotometer in the spectral range [300 –1200 nm] and the XRD diffraction was used to identify the crystalline structure of the processed BiOI/TiO2 NTs nanocomposites. A diffractometer with a Cu Kα anode (λ = 0.1542 nm) operating at 40 kV and 30 mA was used. The as-prepared NCs, specifically BiOI/TiO2 NTs, were designed for the photocatalytic degradation of methylene Blue (MB). X-ray diffraction analysis revealed the formation of the TiO2 anatase phase and polycrystalline BiOI films in all processed NCs. UV/Vis measurements indicated a shift in the nanocomposite’s active region from UV to visible light. The highest absorption and the lowest bandgap energy (Eg value, ∼2 eV) were observed in the NCs with 5 BiOI cycles. The photocurrent density reached 27 μA cm−2, approximately three times higher than the photocurrent density exhibited by TiO2 nanotubes under similar conditions. The optimal photocatalytic rate was achieved with BiOI/TiO2 NCs processed after five SILAR cycles.

Electrochemical nanosensor based on Ag-doped TiO2 nanotubes for detecting ascorbic acid

This work describes the development of an electrochemical nanosensor for the quantitative determination of ascorbic acid (AA). The transducer and receptor system of the nanosensor is based on a silver-doped titanium oxide nanotube (Ag-TiO2NTs) electrode synthesized by a one-step electrochemical anodization method followed by an annealing treatment. The synthesis was carried out at a constant potential of 30 V for 45 min in an organic electrolyte in the presence of F- ions and the dopant. The obtained structure was then subjected to morphological and compositional analysis. In addition, its analytical response to ascorbic acid was evaluated. The analytical techniques employed included scanning electron microscopy (SEM), X-ray diffraction (DRX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The results demonstrate the growth of a highly ordered nanotube array with average dimensions of 80 nm, 19 nm and 1660 nm for diameter, wall thickness and length, respectively, and suggest a major composition of silver-doped titanium oxide. The synthesized Ag-TiO2NTs successfully recorded electroanalytical activity for ascorbic acid, with a non-reversible, diffusion-controlled, and mostly capacitive electrochemical profile. It showed low resistance to change transfer and registered a sensitivity of 216.24μA/(mM∙cm2) and a detection limit of 11.1 μM in a linear range of 840–4000 μΜ. The sensor demonstrated repeatability and reproducibility with RSD values of 5.5% and 2.8%, respectively. In addition, it showed selectivity for AA in the presence of glucose at AA/GLU values (1:1, 1:10 and 1:100).

Electrochemical Strategies for the Formation of Iron Oxide Nanostructures: Enhancing Photoelectrochemical Performance for Energy and Environmental Applications

Using hematite (α‐Fe2O3) nanostructures as photoanodes for photoelectrochemical (PEC) water splitting has received widespread attention in recent years due to their superior PEC performance. However, hematite has a short charge‐carrier lifetime, which hampers the construction of commercial photovoltaic devices. Various electrochemical methods for fabricating hematite and adjusting their physical properties to overcome these drawbacks are reported. This review introduces electrochemical deposition and anodization methods to form hematite nanostructures and explores post‐treatments to enhance their properties for application in advanced PEC devices.

Ni-TiO2 nanotube arrays for highly sensitive and selective detection of acetone vapor

To further improve the acetone sensing performance of TiO2 nanotube arrays synthesized by an electrochemical anodization method, the Ni dopants in lower variable valences than Ti4+ ions were introduced into TiO2 nanotube arrays via a hydrothermal method. At the prime operating temperature of 420 °C, the Ni-TiO2 nanotube arrays-based sensor showed almost three times higher acetone vapor response (29.5–100 ppm) than the TiO2 sensor, as well as a higher degree of linearity (R2 = 0.99) and sensitivity (slope = 1.03) to 1–500 ppm acetone, faster response/recovery speed (1.8/88.3 s), higher long term stability (29.5 ± 1.9 %), and better selectivity against toluene, alcohol, methoxythanol, methanol, DMF, glycol, hydrogen, and ammonia. As revealed by XRD, SEM, and XPS, the improved acetone sensing performance of Ni-TiO2 nanotube arrays should be contributed by the substitution of the smaller Ni2+/Ni3+ ions for the larger Ti4+ ions in TiO2 lattice which yielded the reduction of nanotube thickness and average crystallite size, as well as the increase in the content of OV on the surface.

Highly broadband plasmonic Pt nanoparticles modified α-Fe2O3/TiO2 nanotubes for efficient photoelectrochemical water splitting

In order to develop an efficient photocatalyst electrode for water splitting and solar energy harvesting in the visible region, TiO2 nanotubes arrays (TiNT) modified by hematite (α-Fe2O3) and broadband plasmonic platinum (Pt) nanoparticles have been successfully synthesized via electrochemical anodization and electrodeposition methods. α-Fe2O3 and Pt nanoparticles were electrodeposited on TiNT at different durations, namely 25, 50 and 100s.Interestingly, compared with pure TiNT, important improvement in photocurrent densities and photoconversion efficiencies were found. The optimal Pt nanoparticle size (50–90 nm), achieved at a deposition time of 50s, resulted in a stronger visible light absorption and much higher photocurrent. Pt(50s)/TiNT photoelectrode reached photocurrent density value of 2.3 mA/cm2 at 1.23 V vs. RHE, which is more than 100 times that of pristine TiNT. An impressive maximum photoconversion efficiency of about 10% was reached by Pt/α-Fe2O3/TiNT photoelectrode. The improved photoelectrochemical activity of the photoelectrode can be ascribed to the better absorption of visible light due to the presence of optimally sized Pt nanoparticles with surface plasmon resonance effect (SPR) and more efficient charge separation/transport owing to the presence of α-Fe2O3/TiNT heterojunction.

Nd-Gd–Platinum doped TiO2 nanotube arrays catalyst for water splitting in Alkaline Medium

The utilization of a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) plays an important role in energy conversion in regard to the development of hydrogen-based clean energy sources. The HER in alkaline media by co-doped lanthanide-platinum TiO2 Nanotube Arrays (TNTA) catalyst electrodes has yet to be studied. Here, we report the robust fabrication of an electrocatalyst and its prominent performance in catalyzing the HER. The catalyst electrode consisted of TiO2 nanotube arrays doped with rare earth metals (neodymium (Nd) and gadolinium (Gd)) and a small loading of Pt metal as double-layer nanotube arrays. This material was obtained by a two-step electrochemical anodization method using a small amount of fluoride salt and a short time of mechanical growth. Additionally, an in situ doping strategy that utilized a hydrothermal treatment for the ternary and quaternary ions of Nd, Gd and Pt was performed, while retaining the anatase phase. The Nd-Gd-TNTA catalyst electrode produced a current density of −47.522 µA cm−2 and exhibited a low activation energy of approximately 2.15 kJ/mol. The Nd-Gd-Pt-TNTA catalyst electrode is the best candidate for supporting the HER and advancing water splitting techniques for high-purity hydrogen production in alkaline media.

Application of an Eco-Friendly Adhesive and Electrochemical Nanostructuring for Joining of Aluminum A1050 Plates

In adhesive joints used in several industrial applications, the adherends' bonding is made using an adhesive, which is usually an epoxy resin. However, since these adhesives are derived from petroleum fractions, they are harmful to the environment, due to the pollutants produced both during their manufacture and subsequent use. Thus, in recent years, effective steps have been made to replace these adhesives with ecological (green) ones. The present work focuses on the study of aluminum A1050 joints bonded with a green adhesive; the study also involves the electrochemical anodization method applied to adherends for nano-functionalization. The nanostructured aluminum adherends allow the formation of an expanded surface area for adhesion, compared to the non-anodized adherends. For comparison reasons, two different adhesives (Araldite LY1564 and Green Super Sap) were used. In addition, for the same reasons, both anodized and non-anodized aluminum adherends were joined with both types of adhesives. The lap joints were subsequently tested under both shear-tension and three-point bending conditions. The major findings were that aluminum A1050 anodization in all cases resulted in shear strength enhancement of the joints, while joints with both aluminum anodized and non-anodized adherends and bonded with the eco-friendly adhesive showed a superior shear behavior as compared to the respective joints bonded with Araldite adhesive.

Impact of Annealing on ZrO2 Nanotubes for Photocatalytic Application

This work aims to study the structural, optical, and photocatalytic properties of ZrO2 nanotubes (NTs) that have been synthesized using the electrochemical anodization method. The structural and morphological characteristics of unannealed and annealed (400 °C, 500 °C, and 700 °C) ZrO2 NTs were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Details of the structural and morphological results are depicted to clarify the effect of annealing temperature on the NTs. Furthermore, the reflectivity and photoluminescence of ZrO2 NTs were found to depend on the annealing temperature. The resulting bandgap values were 3.1 eV for samples annealed at 400 °C and 3.4 eV for samples annealed at 550 and 700 °C. Thus, amorphous and annealed ZrO2 NTs were tested in terms of their photocatalytic degradation of Black Amido (BA) dye. Samples annealed at 400 °C exhibited 85.4% BA degradation within 270 min compared to 77.5% for samples annealed at 550 °C and 70.2% for samples annealed at 700 °C. The anodized ZrO2 NTs that were annealed at 400 °C showed the coexistence of tetragonal and monoclinic crystalline phases and exhibited the fastest photocatalytic performance against the BA dye. This photocatalytic behavior was correlated to the crystalline phase transformation and the structural defects seen in anodized ZrO2.

Electrochemical Oxidation to Fabricate Micro-Nano-Scale Surface Wrinkling of Liquid Metals.

Constructing wrinkled structures on the surface of materials to obtain new functions has broad application prospects. Here a generalized method is reported to fabricate multi-scale and diverse-dimensional oxide wrinkles on liquid metal surfaces by an electrochemical anodization method. The oxide film on the surface of the liquid metal is successfully thickened to hundreds of nanometers by electrochemical anodization, and then the micro-wrinkles with height differences of several hundred nanometers are obtained by the growth stress. It is succeeded in altering the distribution of growth stress by changing the substrate geometry to induce different wrinkle morphologies, such as one-dimensional striped wrinkles and two-dimensional labyrinth wrinkles. Further, radial wrinkles are obtained under the hoop stress induced by the difference in surface tensions. These hierarchical wrinkles of different scales can exist on the liquid metal surface simultaneously. Surface wrinkles of liquid metal may have potential applications in the future for flexible electronics, sensors, displays, and so on.

Defect-rich ultrafine amorphous tin oxyhydroxide nanoparticle anode for high-performance lithium-ion batteries

Metal oxyhydroxide nanostructures are attractive anode materials for lithium-ion batteries (LIBs) because of their appreciable theoretical capacity. In their amorphous phase they can greatly relieve volume changes during cycling, enhancing cycle stability. Here, we successfully produce amorphous tin oxyhydroxide nanoparticles (a-SnOOH NPs) with sizes of less than 5 nm using a facile electrochemical anodization method. Plentiful oxygen vacancies (VOs) are generated in the NPs by simply introducing glycerol into the electrolyte. The numerous defects further facilitate the electrochemical kinetics of the a-SnOOH NPs with rich VOs (a-SnOOH/VO NPs), resulting in better cell performance. With the synergetic combination of amorphous nature and abundant defect sites, the a-SnOOH/VO NP anode for LIBs exhibits a considerable initial discharge capacity of 2171.3 mAh/g at a current rate of 0.2 C and retains a high reversible capacity with a coulombic efficiency of 98.4% after 300 cycles. The ultrafine particles also deliver exceptional rate capability with a large capacity of 641.9 mAh/g even at a high current rate of 20 C.

Pyrite (FeS2)‐decorated 1D TiO2 nanotubes in a bilayer as a sustainable photoanode for photoelectrochemical water splitting activity

AbstractHerein, FeS2@TiO2 nanotubes photocatalyst was prepared by electrochemical anodization method followed by successive ionic layer adsorption and reaction method, and then finally annealed in a tube furnace for homogenous crystallization. The surface morphology, elemental composition, optical properties, and crystalline structure of the prepared FeS2@TiO2 nanocomposite were found out by performing scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffraction, UV–Vis diffuse reflectance spectroscopy, and fluorescence spectroscopy, respectively, while bonds vibrations and various functional groups' presence were analyzed using Raman and Fourier transform infrared spectroscopy. A higher photocurrent density of 1.59 mA/cm2 at 0.3 V versus reference electrode of Ag/AgCl (1.23 V versus reversible hydrogen electrode) using 100 mW/cm2 intensive light source was shown by 15‐FeS2@TiO2 nanotubes (uniformly loaded photoanode) while donor density (ND) of 3.68 × 10−13 cm−3 as compared to pure TiO2 NTs (0.09 mA/cm2), 05‐FeS2@TiO2 NTs (0.19 mA/cm2), 10‐FeS2@TiO2 NTs (0.53 mA/cm2) and 20‐FeS2@TiO2 NTs (0.61 mA/cm2), respectively. The exceptional photoelectrochemical activity results were attributed to the homogenous integration of FeS2 that not only increase the charge separation but also, intensively interacted with the substrate (TiO2 nanotubes), which results in an excellent photoelectrochemical activity.

Synthesis of high-quality graphene by electrochemical anodic and cathodic co-exfoliation method

Large-scale preparation of high-quality graphene nanosheets at low cost is critical for advancing its industrial applications. Here we propose a fast electrochemical anode and cathode co-exfoliation method to synthesize high-yield solution-processable graphene. The chosen tetrabutylammonium hexafluorophosphate molecule, with superior electrochemical stability and oxygen-free feature, could efficiently enable simultaneous anion and cation intercalation while suppressing structural damage from anodic oxidation, resulting in minimally destructive exfoliation and high-efficiency graphene synthesis. After accurately regulating the intercalation chemistry, high-yield graphene (75% and 92% for anode and cathode, respectively) with uniform thickness distribution (>75%, 1–3 layers) was obtained. Meanwhile, as-prepared graphene has ultralow defect density (ID/IG < 0.052), significantly high C/O ratio (>46.6) and exceptional electrical conductivity (>4 × 104 S m−1). Remarkably, record high production rates (over 100 g h−1) are achieved in up-scaled fabrication process, and such graphene quality and exfoliation efficiency outperform most previously reported research. Furthermore, the graphene based flexible supercapacitor exhibits a high area capacitance of 95 mF cm−2, excellent rate capability, cycling performance with 99% after 10,000 cycles and robust mechanical flexibility. This efficient and scalable process will promote the mass production of high-quality graphene, which offers great potential applications in wearable electronics.

Performance of Pandannus amaryllifolius dye on zinc oxide nanoflakes synthesized via electrochemical anodization method

This work presents a study on the effect of Pandanus amaryllifolius dye on the optical properties of zinc oxide nanoflakes synthesized via anodization method. ZnO films were synthesized by anodization method at different applied potentials of 4,8,12 and 16 V under optimum anodization time of 60 min. The synthesized samples were studied and characterized through X-Ray Diffraction, Ultraviolet-Visible spectroscopy and Field Emission Scanning Microscope to evaluate their crystallinity, UV absorption, and surface morphological properties, respectively. The results showed that 12 V sample had the highest (100), (101) and (110) XRD intensity for ZnO and the intensity of the main peak (101) increased by approximately 50% after the adsorption of P. amaryllifolius dye. From the FESEM result, 12 V ZnO exhibited the most closely packed growth of nanoflakes. For optical properties characterized by UV-Vis, there was a significant 10% higher UV absorption sustained between 220–370 nm for the dye treated.

Formation of Titania Nanowires and Nanorods on Ti-6Al-4V Alloy Using Electrochemical Anodization

The formation of titania (TiO2) nanowires and nanorods by various methods has been reported in the past. The current work, for the first time, describes the formation of TiO2 nanowires and nanorods by using the electrochemical anodization method in 0.5 wt% hydrogen fluoride (HF) based aqueous electrolyte on Ti-6Al-4V alloy. Likewise, the TiO2 nanotubes were grown on a titanium plate. The anodization voltage was varied, while temperature and time, were kept constant. The morphological and crystallographic characterization of the samples was performed.