The transition toward low-carbon energy systems has intensified interest in sustainable hydrogen production technologies. One of the most promising methods for producing green hydrogen is water electrolysis powered by renewable energy. This work reviews recent advances in electrode materials used in four major electrolysis technologies: alkaline (ALK), proton exchange membrane (PEM), solid oxide electrolysis cells (SOEC), and anion exchange membrane (AEM). A bibliometric analysis of scientific publications from 2021 to 2025 highlights the rapid growth of research and the increasing importance of electrode materials in improving electrolysis performance. Operating environments, material requirements, and catalytic properties are compared across these systems. Recent developments in electrocatalysts—including transition-metal alloys, heterostructured catalysts, defect-engineered materials, and nanostructured systems—are evaluated in terms of catalytic activity, durability, and scalability. Particular attention is given to reducing noble metal usage while maintaining high electrochemical performance. Results indicate that transition-metal-based catalysts and engineered interfaces can achieve activity comparable to noble-metal systems while offering better cost efficiency. However, challenges related to long-term durability, large-scale synthesis, and standardized testing persist. Continued interdisciplinary research in materials design and electrochemical engineering is essential to enable efficient, durable, and cost-effective green hydrogen production.

Nanoporous gold (np-Au) has attracted significant attention for biomedical and electrochemical applications due to its high surface area, tunable morphology, and excellent biocompatibility. In this study, polycrystalline gold surfaces were modified by anodization in 0.3-0.9 M oxalic acid to produce np-Au layers. The influence of anodization conditions on surface morphology, chemical composition, electronic properties, and corrosion resistance in artificial saliva was systematically investigated. Surface morphology and porosity were analyzed by scanning electron microscopy combined with image analysis, revealing a transition from fine and uniform porosity to highly developed but structurally heterogeneous nanoporous structures with increasing oxalic acid concentration. Energy-dispersive spectroscopy confirmed surface oxidation and adsorption of oxygen- and carbon-containing species after anodization, while gold remained the dominant component. Scanning Kelvin probe measurements demonstrated significant modifications of surface electronic properties, including changes in contact potential difference, governed by nanostructure geometry and surface chemistry. Electrochemical tests in artificial saliva showed that increasing nanoporousness led to reduced thermodynamic stability, with the sample anodized in 0.3 M oxalic acid providing the most favorable balance between corrosion resistance and surface activity. These results demonstrate that oxalic acid anodization is a simple and effective approach for tailoring gold surfaces for biomedical applications, particularly in dentistry.

NiTi alloys are widely used in biomedical applications due to their shape memory and superelastic properties. However, their surface reactivity requires protective, biofunctional coatings. To enhance NiTi performance, its surface was modified with an Ag-SiO2-TiO2 nanocoating containing small amounts of silica and silver. The coating’s primary phase was rutile with structural defects and a silver solid solution. It showed good adhesion, high scratch resistance, and improved corrosion behavior in Ringer’s solution, as demonstrated by EIS and cyclic polarization. EIS revealed high low-frequency impedance and two time constants, suggesting both barrier protection and slower electrochemical processes. Despite low breakdown and repassivation potentials, the coating effectively limited uniform corrosion. SEM/EDS confirmed localized degradation and partial substrate exposure, while elemental mapping showed well-dispersed silica and silver in a TiO2-rich matrix. The proposed pitting mechanism involves chloride-induced depassivation and galvanic effects. Surface potential mapping indicated electrostatic heterogeneity, mitigated by silica. The coating offers a balanced combination of corrosion protection and biofunctionality, supporting its potential for implant use.

The development of dental implants has significantly advanced due to technological innovations aimed at improving their performance and patient outcomes. This work presents key factors influencing the success of dental implants, including osseointegration, which is the direct connection between living bone and the implant surface, and the various surface modifications that enhance this process. This review highlights the importance of surface roughness, chemical composition, and the use of bioactive coatings to promote better integration with surrounding bone tissue. Innovations such as nanotechnology, 3D printing, and smart surfaces are paving the way for more effective and personalized dental implant solutions. This review underscores the importance of ongoing research and development to improve success rates, enhance patient comfort, and reduce healing times. It focuses on creating cost-effective, reliable methods that integrate multiple functions, such as combining antibacterial and osteoconductive properties to improve overall implant performance.

Titanium alloys are widely used in orthopedic and dental implants, yet their limited bioactivity and bacterial resistance remain critical challenges. This study aimed to enhance the surface performance of a Ti-13Zr-13Nb alloy through the formation of a porous oxide layer and the application of a bioactive, drug-loaded coating. Porous oxide layers composed of Ti, Zr, and Nb oxides with fluoride incorporation were fabricated using a novel anodizing process. The fluoride-assisted electrochemical mechanism controlling oxide growth was elucidated through SEM and EDS analyses. The anodized surface exhibited reduced microhardness, beneficial for minimizing stress-shielding effects. Subsequently, chitosan–tetracycline composite coatings were produced via EPD and compared with dip-coating method. Characterization by ATR-FTIR, optical microscopy, SEM, and UV-VIS spectroscopy confirmed the formation of uniform, adherent, and moderately porous coatings with sustained drug release when produced by EPD, while dip-coated layers were less homogeneous and released the drug faster. Microhardness testing revealed improved mechanical integrity of EPD coatings. The developed chitosan–tetracycline–oxide layer system provides tunable nano/microgram-scale drug release and enhanced surface functionality, offering promising perspectives for acute and medium-term regenerative and antibacterial biomedical applications.

This review covers the latest issues related to the development of medical technologies based on chitosan coatings. The progress of modern implantology requires medicine to adapt constantly to new opportunities and challenges. Infections may occur at the implantation site or in the body and may require treatment with antibiotics or surgery to resolve them. Due to its unique properties, such as biocompatibility, biodegradability, non-toxicity and antibacterial activity, chitosan has been proposed to be co-deposited with biocidal silver nanoparticles in the form of nanocomposite coatings on the surface of metallic implants to extinguish local inflammations. The mechanism of co-deposition of chitosan with metal ions and particles using electrophoretic deposition has not yet been thoroughly explained. This, among others, results from a number of factors that influence the process and their mutual relations. Therefore, the present review aims at a deeper understanding of the mechanism of creating chitosan-silver nanocomposite coatings.

The review discusses the latest issues related to using chitosan, a biocompatible and biodegradable polymer derived from chitin, as a carrier in intelligent drug-delivery systems. The continuous development of medicine and rapid technological progress pose new challenges in designing new therapeutic agents. Chitosan has properties that make it suitable for drug-delivery applications, such as its ability to form nanoparticles and its mucoadhesion that enhance drug absorption. Chitosan can be combined with antibiotics, analgesics and other ingredients with specific properties. While chitosan is not medicinal substance, it can be a carrier in controlled drug-release systems.

Biomaterials are the basis for the development of medicine because they allow safe contact with a living organism. The aim of this work was to produce innovative oxide layers with a microporous structure on the surface of commercially pure titanium Grade 4 (CpTi G4) and to characterize their properties as drug carriers. The anodization of the CpTi G4 subjected to mechanical grinding and electrochemical polishing was carried out in a solution of 1M ethylene glycol with the addition of 40 g of ammonium fluoride at a voltage of 20 V for 2, 18, 24, and 48 h at room temperature. It was found that the longer the anodization time, the greater the number of pores formed on the CpTi G4 surface as revealed using the FE-SEM method, and the greater the surface roughness determined in profilometric tests. As the anodizing time increases, the amount of the drug in the form of gentamicin sulfate incorporated into the resulting pores decreases. The most favorable drug release kinetics profile determined via UV–VIS absorption spectroscopy was found for the CpTi G4 anodized for 2 h.

To functionalize the NiTi alloy, multifunctional innovative nanocoatings of Ag-TiO2 and Ag-TiO2 doped with hydroxyapatite were engineered on its surface. The coatings were thoroughly characterized, focusing on surface topography and key functional properties, including adhesion, surface wettability, biocompatibility, antibacterial activity, and corrosion resistance. The electrochemical corrosion kinetics in a simulated body fluid and the mechanisms were analyzed. The coatings exhibited hydrophilic properties and were biocompatible with fibroblast and osteoblast cells while also demonstrating antibacterial activity against E. coli and S. epidermidis. The coatings adhered strongly to the NiTi substrate, with superior adhesion observed in the hydroxyapatite-doped layers. Conversely, the Ag-TiO2 layers showed enhanced corrosion resistance.

Preventing or treating infections at implantation sites where the risk of bacterial contamination is high requires the development of intelligent drug delivery systems. The objective of this work was to develop a production method and characterization of fourth-generation oxide nanotubes on titanium grade 4 surface as a potential drug carrier. This study focused on the anodizing process; physico-chemical characterization using FE-SEM, EDS, and FTIR; in vitro corrosion resistance in an artificial saliva solution; and determining the drug release kinetics of gentamicin sulfate using UV-VIS. The anodizing process was optimized to produce fourth-generation oxide nanotubes in a fluoride-free electrolyte, ensuring rapid growth and lack of order. Results showed that the length of the oxide nanotubes was inversely proportional to the anodizing voltage, with longer nanotubes formed at lower voltages. The nanotubes were shown to have a honeycomb structure with silver particles co-deposited on the surface for antibacterial properties and were capable of carrying and releasing the antibiotic gentamicin sulfate in a controlled manner, following Fick’s first law of diffusion. The corrosion resistance study demonstrates that the oxide nanotubes enhance the corrosion resistance of the titanium surface. The oxide nanotubes show promise in enhancing osseointegration and reducing post-implantation complications.

The use of green hydrogen as a high-energy fuel of the future may be an opportunity to balance the unstable energy system, which still relies on renewable energy sources. This work is a comprehensive review of recent advancements in green hydrogen production. This review outlines the current energy consumption trends. It presents the tasks and challenges of the hydrogen economy towards green hydrogen, including production, purification, transportation, storage, and conversion into electricity. This work presents the main types of water electrolyzers: alkaline electrolyzers, proton exchange membrane electrolyzers, solid oxide electrolyzers, and anion exchange membrane electrolyzers. Despite the higher production costs of green hydrogen compared to grey hydrogen, this review suggests that as renewable energy technologies become cheaper and more efficient, the cost of green hydrogen is expected to decrease. The review highlights the need for cost-effective and efficient electrode materials for large-scale applications. It concludes by comparing the operating parameters and cost considerations of the different electrolyzer technologies. It sets targets for 2050 to improve the efficiency, durability, and scalability of electrolyzers. The review underscores the importance of ongoing research and development to address the limitations of current electrolyzer technology and to make green hydrogen production more competitive with fossil fuels.

The use of green hydrogen as a high-energy fuel of the future may be an opportunity to balance the unstable energy system, which still remains renewable energy sources. This work is a comprehensive review of recent advancements in green hydrogen production. The review outlines the current energy consumption trends. It presents the tasks and challenges of the Hydrogen Economy towards green hydrogen, including production, purification, transmission, storage, and conversion into electricity. This work discusses the main types of water electrolyzers: alkaline electrolyzers, proton exchange membrane electrolyzers, solid oxide electrolyzers, and anion exchange membrane electrolyzers. Despite the higher production costs of green hydrogen compared to grey hydrogen, the review suggests that as renewable energy technologies become cheaper and more efficient, the cost of green hydrogen is expected to decrease. The review highlights the need for cost-effective and efficient electrode materials for large-scale applications. It concludes by comparing the operating parameters and cost considerations of the different electrolyzer technologies. It sets targets for 2050 to improve the efficiency, durability, and scalability of electrolyzers. The review underscores the importance of ongoing research and development to address the limitations of current electrolyzer technology and to make green hydrogen production more competitive with fossil fuels.

Surface modifications not only improve the corrosion resistance of Co-Cr-Mo dental alloys (Bego Wirobond® C) but also ensure their long-term performance and reliability in dental applications. This paper describes the preparation of single-layer TiO2-ZrO2 sol–gel coatings on the Co-Cr-Mo dental alloy using the method of dip-coating. The TiO2-ZrO2 sol–gel coatings were sintered at 300 and 500 °C. SEM analysis shows that sintering at 300 °C produces a uniform, slightly dense structure without micro-cracks, while sintering at 500 °C results in a denser structure with micro-cracks due to higher stress and shrinkage. EDS confirms that sintering temperature affects the elemental composition of the coating, with higher temperatures causing the volatilization or diffusion of Ti and Zr. Roughness measurements indicate that the Ra value increases with the sintering temperature, meeting dental application requirements. Electrochemical measurements by open-circuit potential, EIS, and cyclic potentiodynamic curves demonstrate that sintering temperature and saliva composition affect corrosion resistance, with NaF and mouthwashes (Listerine Total Care Teeth Protection® and Meridol®) generally increasing charge transfer resistance and double-layer capacitance. The ceramic TiO2-ZrO2 coatings significantly reduce pitting corrosion susceptibility at physiological and acidic pH, with the 500 °C sintered coating showing better protective properties. These findings highlight the potential of TiO2-ZrO2 coatings in enhancing the performance of Co-Cr-Mo dental alloys.

Carbon nanotubes are a promising material for use in innovative biomedical solutions due to their unique chemical, mechanical, electrical, and magnetic properties. This work provides a method for the development of ultrasonically assisted electrophoretic deposition of multi-walled carbon nanotubes on a CoCrMo dental alloy. Functionalization of multi-walled carbon nanotubes was carried out by chemical oxidation in a mixture of nitric and sulfuric acids. The modified and unmodified multi-walled carbon nanotubes were anaphoretically deposited on the CoCrMo alloy in an aqueous solution. Chemical composition was studied by Fourier transform infrared spectroscopy. Surface morphology was examined by scanning electron microscopy. The mechanism and kinetics of the electrochemical corrosion of the obtained coatings in artificial saliva at 37 °C were determined using the open-circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The capacitive behavior and high corrosion resistance of the tested electrodes were revealed. It was found that the kinetics of electrochemical corrosion of the CoCrMo electrode significantly decreased in the presence of the functionalized multi-walled carbon nanotube coating. Electrophoretic deposition was shown to be an effective, low-cost, and fast method of producing nanotubes with controlled thickness, homogeneity, and packing density.

The biomedical Ti–13Zr–13Nb bi-phase (α + β) alloy for long-term applications in implantology has recently been developed. The porous oxide nanotubes’ (ONTs) layers of various geometries and lengths on the Ti–13Zr–13Nb alloy surface can be produced by anodizing to improve osseointegration. This work was aimed at how anodizing conditions determinatine the micromechanical and biotribological properties of the Ti–13Zr–13Nb alloy. First-generation (1G), second-generation (2G), and third-generation (3G) ONT layers were produced on the Ti–13Zr–13Nb alloy surface by anodizing. The microstructure was characterized using SEM. Micromechanical properties were investigated by the Vickers microhardness test under variable loads. Biotribological properties were examined in Ringer’s solution in a reciprocating motion in the ball-on-flat system. The 2D roughness profiles method was used to assess the wear tracks of the tested materials. Wear scars’ analysis of the ZrO2 ball was performed using optical microscopy. It was found that the composition of the electrolyte with the presence of fluoride ions was an essential factor influencing the micromechanical and biotribological properties of the obtained ONT layers. The three-body abrasion wear mechanism was proposed to explain the biotribological wear in Ringer’s solution for the Ti–13Zr–13Nb alloy before and after anodizing.

The success of implant treatment is dependent on the osseointegration of the implant. The main goal of this work was to improve the biofunctionality of the Ti-13Nb-13Zr implant alloy by the production of oxide nanotubes (ONTs) layers for better anchoring in the bone and use as an intelligent carrier in drug delivery systems. Anodization of the Ti-13Nb-13Zr alloy was carried out in 0.5% HF, 1 M (NH4)2SO4 + 2% NH4F, and 1 M ethylene glycol + 4 wt.% NH4F electrolytes. Physicochemical characteristics of ONTs were performed by high-resolution electron microscopy (HREM), X-ray photoelectron spectroscopy (XPS), and scanning Kelvin probe (SKP). Water contact angle studies were conducted using the sitting airdrop method. In vitro biological properties and release kinetics of ibuprofen were investigated. The results of TEM and XPS studies confirmed the formation of the single-walled ONTs of three generations on the bi-phase (α + β) Ti-13Nb-13Zr alloy. The ONTs were composed of oxides of the alloying elements. The proposed surface modification method ensured good hemolytic properties, no cytotoxity for L-929 mouse cells, good adhesion, increased surface wettability, and improved athrombogenic properties of the Ti-13Nb-13Zr alloy. Nanotubular surfaces allowed ibuprofen to be released from the polymer matrix according to the Gallagher–Corrigan model.

Surface charge and in vitro corrosion resistance are some of the key parameters characterizing biomaterials in the interaction of the implant with the biological environment. Hence, this work investigates the in vitro bioelectrochemical behavior of newly developed oxide nanotubes (ONTs) layers of second-generation (2G) on a Ti–13Zr–13Nb alloy. The 2G ONTs were produced by anodization in 1 M (NH4)2SO4 solution with 2 wt.% of NH4F. The physical and chemical properties of the obtained bamboo-inspired 2G ONTs were characterized using scanning electron microscopy with field emission and energy dispersive spectroscopy. Zeta potential measurements for the examined materials were carried out using an electrokinetic analyzer in aqueous electrolytes of potassium chloride, phosphate-buffered saline and artificial blood. It was found that the electrolyte type and the ionic strength affect the bioelectrochemical properties of 2G ONTs layers. Open circuit potential and anodic polarization curve results proved the influence of anodizing on the improvement of in vitro corrosion resistance of the Ti–13Zr–13Nb alloy in PBS solution. The anodizing conditions used can be proposed for the production of long-term implants, which are not susceptible to pitting corrosion up to 9.4 V.

This work concerns the search for new ways to modify the surface of the biomedical Ti–13Zr–13Nb alloy for applications in regenerative medicine and personalized medicine. Obtained for the first time, oxide nanotubes (ONTs) layers of first-generation (1G) on a Ti–13Zr–13Nb alloy were produced by anodizing in 0.5% HF electrolyte at 20 V for 120 min. The physico-chemical characterization of the obtained bamboo-inspired 1G ONTs was conducted using TEM and ATR-FTIR methods. In vitro corrosion resistance of the 1G ONTs and comparative Ti–13Zr–13Nb substrate in saline solution at 37 °C was conducted by open-circuit potential, Tafel curves, anodic polarization curves, and EIS methods. LEIS and SVET study of local corrosion resistance was also carried out. It was found that surface modification by anodizing of the Ti–13Zr–13Nb alloy under proposed conditions allowed to obtain porous ONTs highly resistant to pitting corrosion. The obtained results give a new insight into the relationship between the morphological parameters of first-generation oxide nanotubes and in vitro corrosion resistance of the Ti–13Zr–13Nb alloy in saline solution at the macro- and microscale.

We determined the in vitro corrosion resistance of the composite chitosan-silver(I) [Ag(I)] ion coating on the cobalt-chromium-molybdenum (CoCrMo) dental alloy in a 0.9% sodium chloride (NaCl) solution at 37°C. We obtained the novel composite chitosan–Ag(I) ion coating by electrophoretic deposition at 20 V for 30 s at room temperature in a 2% (v/v) aqueous solution of acetic acid with 1 g dm–3 chitosan and 10 g dm–3 silver nitrate. We evaluated the chemical composition with energy dispersive spectroscopy and Fouriertransform infrared spectroscopy. We investigated surface topography and electronic properties with a scanning Kelvin probe. We determined the mechanism and kinetics of the electrochemical corrosion of the obtained coatings by electrochemical impedance spectroscopy. The Ag content in the composite chitosan–Ag(I) ion coating was 1.9 ± 1 wt.%. The cataphoretic co-deposition of chitosan and Ag(I) ions in an aqueous solution can be used to modify the CoCrMo alloy surface to obtain new coatings with antibacterial properties.

The pitting corrosion of orthodontic apparatus elements in the oral environment is an interest of both clinicians and scientists dealing with the assessment of the biocompatibility of medical materials. This work presents a study on the effect of ready-to-use Listerine® and Meridol® mouthwashes and sodium fluoride on the resistance of the commercial Remanium®-type orthodontic archwire to pitting corrosion in artificial saliva at 37 °C. XRD, SEM, EDS, mechanical properties, and microhardness measurements were used to characterize the archwire. The in vitro corrosion resistance of the archwire was examined using the open-circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The physicochemical characteristics confirmed the presence of a bi-phase alloy with a mixed austenite/ferrite structure containing Fe 74.4(7) at.%, Cr 18.4(4) at.%, and Ni 7.2(4) at.%. The Fe–Cr–Ni alloy was characterized by high tensile strength and Vickers microhardness. EIS revealed the capacitive behavior with high corrosion resistance. It was found that the kinetics of pitting corrosion in the artificial saliva decreased in the presence of NaF and mouthwashes. The potentiodynamic characteristics confirmed the decrease in susceptibility to pitting corrosion after the modification of artificial saliva. The pitting corrosion mechanism of the self-passive oxide layer on the surface of the Fe–Cr–Ni electrode in the biological environment containing chloride ions was discussed in detail. Mechanical properties after corrosion tests were weakened.