Nanotubular Structures Research Articles

Structural and morphological studies of g-C3N4-functionalized MWCNTs nanocomposite for sunlight-responsive photocatalytic activity

Photocatalytic degradation of organic contaminants has been proven to be one of the greatest economical and efficient techniques to address environmental pollution problems. Multi-walled carbon nanotubes (MWCNTs)/g-C3N4 (GCN) nanocomposites (NCs) were synthesized by a hydrothermal process aided by ultrasound to produce active photocatalysts. The effective synthesis of GCN, MWCNTs, and MWCNTs/GCN NCs was confirmed by X-ray diffraction (XRD) patterns. The fabrication of GCN nanosheets (NSs), the nanotubular structure of MWCNTs, and a network of neuron-like structures for MWCNTs/GCN NCs were all revealed by structural and morphological characterization. The elemental mapping of NCs containing the suitable quantity of MWCNTs revealed a uniform distribution of the sample's component elements. When the optical properties of the fabricated nanomaterials were examined by employing UV–visible spectroscopy, the results revealed a blue shift (a shift of maximum absorption to the UV region), which suggests that the addition of MWCNTs increased the band-gap energy. The behaviour of e––h+ pair recombination was revealed by measuring the charge carrier movement and trapping efficiency using photoluminescence (PL) spectroscopy. Crystal violet (CV) dye was photocatalytically degraded using prepared NCs in the presence of sunlight, and the synergistic effects of GCN and MWCNTs were examined. With a degradation efficiency of 99.32 %, MWCNTs/GCN NCs demonstrated the best sunlight-irradiated photocatalytic activity for CV degradation. The degradation of CV was discovered to follow pseudo-first-order kinetics. Throughout five consecutive studies, the NCs demonstrated the highest levels of catalytic efficiency and recyclability, with 5 % reduced degrading activities. The trapping tests showed that the primary reactive species involved in the breakdown of CV were the •O2– and •OH radicals.

Comprehensive study on physicochemical properties of materials based on titanium suboxides

This study focuses on the surface structures and microstructural changes of titanium dioxide nanotubes, when electrochemically coated with platinum and/or palladium. Ti samples anodized in a fluorine-containing electrolyte exhibit self-organized nanotubes of varying diameters with open pores. Annealing at 773 K led to compaction of the porous layer, the formation of cracks, and the appearance of corrugation in the nanotubes. The deposition of platinum produced a transition from a nanotubular surface structure to a microcrystalline structure consisting of rutile crystallites. The palladium-coated samples showed fused blocks characteristic of titanium suboxides. The tubular structure was preserved, even after crystallization. SEM images revealed a comb-like pattern in coatings with varying metal content. XRPD analysis confirmed the presence of anatase and elemental titanium. PdO was detected on the surface of the thermally treated samples. For samples co-treated with Pd and Pt, mutual diffusion of the two metals took place during the heat treatment. The findings reveal surface characteristics, metal deposition effects, and phase composition of titania nanotubes, providing valuable insights for further research.

Combined release of LL37 peptide and zinc ion from a mussel-inspired coating on porous titanium for infected bone defect repairing

Implant-associated infections impose great burden on patient health and public healthcare. Antimicrobial peptides and metal ions are generally incorporated onto implant surface to deter bacteria colonization. However, it is still challenging to efficiently prevent postoperative infections at non-cytotoxic dosages. Herein, a scaffold based on porous titanium coated with a mussel-inspired dual-diameter TiO2 nanotubes is developed for loading dual drugs of LL37 peptide and Zn2+ with different sizes and characteristics. Benefiting from in-situ formed polydopamine layer and dual-diameter nanotubular structure, the scaffold provides an efficient platform for controllable drugs elution: accelerated release under acidic condition and sustained release for up to 28 days under neutral/alkalescent circumstances. Such combination of dual drugs simultaneously enhanced antibacterial efficacy and osteogenesis. In antibacterial test, LL37 peptide serving as bacteria membrane puncture agent, and Zn2+ acting as ROS generator, cooperatively destroyed bacterial membrane integrity and subsequently damaged bacterial DNA, endowing dual-drug loaded scaffold with remarkable bactericidal efficiency of > 92 % in vitro and > 99 % in vivo. Noteworthily, dual-drug loaded scaffold promoted bone-implant osteointegration under infectious microenvironment, overmatching single-drug load ones. It provides a promising strategy on surface modification of implant for infected bone defect repairing.

Platinum nanoparticles decorated TiO2 nanotubes for VOCs and bacteria removal in simulated real condition: Effect of the deposition method on the photocatalytic degradation process efficiency

The incorporation of noble metals onto TiO2 nanostructure is considered as a promoting method to enhance the photocatalytic degradation of pollutant in air treatment process. In this study, highly organized TiO2 nanotubes (NTs) were grown by the anodization method of Titanium substrates. The TiO2-NTs were successfully decorated by platinum (Pt) nanoparticles (NPs) using two different deposition methods: (1) electrodeposition and (2) photodeposition.We explore the impact of different deposition methods on the morphology of Pt nanoparticles (NPs) dispersed onto TiO2 nanotubes and the optical characteristics of Pt-TiO2 nanocomposites, investigating their efficacy in photocatalytic degradation We investigate the effect of varying the deposition method on the morphology of Pt-NPs dispersed onto TiO2 nanotubes and the optical properties of the Pt-TiO2 nanocomposites and their efficient photocatalytic activity degradation against Volatile Organic Compounds (VOCs) and bacteria. Scanning and Transmission Electron Microscopy (SEM and TEM) reveal a nanotubular TiO2 anatase structure adorned with Pt NPs, with the quantity and size of NPs contingent upon the deposition technique employed. The photoluminescence (PL) spectra demonstrate that the Pt/TiO2 heterojunction facilitates the separation of photogenerated charges, thereby diminishing carrier recombination rates. To point out the effect of Pt NPS, both pure TiO2 and Pt/TiO2 heterojunction were tested in the photodegradation of Ethyl Acetate (EA). The Pt/TiO2 heterojunction exhibits superior photocatalytic performance compared to TiO2 in EA degradation, regardless of the Pt deposition method employed. Optimal results are achieved with 120 s of Pt electrodeposition and 3 h of Pt photodeposition under visible irradiation, yielding kinetic constants of approximately 0.245 and 0.195 mg.m−3.s−1, respectively, underscoring the pivotal role of the platinum deposition method in pollutant photodegradation. Respectively simultaneous removal of EA and bacteria (Escherichia coli) was tested using Pt and non-Pt decorated TiO2 NTs. We attributed a total degradation of the bacteria after 180 min using the two efficient photocatalysts Electro 120 s and Photo 3 h compared to 60 % of degradation using pure TiO2 nanotubes.

In-Situ Raman Spectroscopy of Li+ and Na+ Storage in Anodic Nanotubes

Anodizing is a high-voltage electrochemical conversion process that forms barrier-type oxide layers or self-organized nanoporous/nanotubular structures. So far, the Al2O3-like nanopores and TiO2-like nanotubes could be successfully synthesized on many valve metals and alloys.Recently, it become possible to form nanotubular structures on iron and consequently control the ratio of hematite (Fe2O3) to magnetite (Fe3O4) by subsequent thermal treatment.1 Electrochemically active nanotubes, such as self-organized TiO2 are of high interest in the battery field due to a unique one-dimensional (1D) geometry offering high volume expansion tolerance and applications without binders and conductive additives. Herein, we report an in - situ Raman spectroscopy study under current control for a better fundamental understanding of Li+/Na+ storage in nanotubes and correlate the structural fingerprints with the electrochemical data on differential capacity plots of d(Q–Q 0) dE –1.2 Real-time measurements revealed that the nanotubes had undergone two major phase transformations with increasing lithium content, disclosing the sequential steps of a lithium intercalation type of storage. In contrast, sodium-ion insertion induced no significant crystal structure modification but instead a slight crystallinity rupture, signifying a dominant nondiffusion-limited capacitive type of storage. The insight into the charge storage in a 1D material in relation to other nanostructures such as nanoparticles3 will be discussed.1. L. Fadillah, D. Kowalski, M. Vincent, C. Zhu, S. Kitano, Y. Aoki and H. Habazaki, ACS Applied Materials & Interfaces , 2023, 15, 52563-52570.2. M. Vincent and D. Kowalski, ACS Applied Nano Materials , 2023, 6, 6528-6537.3. M. Vincent, S. S. Kumar and D. Kowalski, Electrochimica Acta , 2023, 469, 143161. Figure 1

Nanostructured TiO2-X/CuXO-based electrochemical sensor for ultra-sensitive glyphosate detection in real water samples

Glyphosate, a widely employed non-selective pesticide for enhancing crop productivity through weed control, poses significant health and environmental concerns due to its potential link to chronic diseases, cancers, and disruptions in natural symbiotic relationships. Quantifying glyphosate values becomes imperative for effective monitoring and mitigation of associated risks. In response, a novel electrochemical sensor was developed utilizing nanostructured TiO2 films modified with Ti3+ ions and copper oxides for precise detection and quantification of glyphosate in real water samples. The nanotubular structure, synthesized via potentiostatic anodization, underwent further modification through cathodic reduction of Ti4+ to Ti3+ ions and copper electrodeposition. Under optimal experimental conditions, the sensor exhibited a notable ability to detect glyphosate traces by inhibiting peak current in Differential Pulse Voltammetry (DPV). It achieved low limits of detection (LOD = 0.34 pmol/L) and quantification (LOQ = 0.70 pmol/L) within a linear working range of 0.55 to 1000.00 pmol/L. The sensor demonstrated robust stability and excellent precision (repeatability and intermediate precision) without significant variations in analytical response and yielded recovery rates ranging from 91.06 to 99.38 %. These promising results underscore the sensor’s potential application for detecting glyphosate in real aquatic matrices, contributing to effective environmental monitoring and health protection.

Metal-Organic Framework-Derived Au-Doped In2O3 Nanotubes for Monitoring CO at the ppb Level.

Achieving selective detection of ppb-level CO is important for air quality testing at industrial sites to ensure personal safety. Noble metal doping enhances charge transfer, which in turn reduces the detection limit of metal oxide gas sensors. In this work, metal-organic framework-derived Au-doped In2O3 nanotubes with high electrical conductivity are synthesized by pyrolysis of the Au-doped metal-organic framework (In-MIL-68) as a template. Gas-sensing experiments reveal that the detection limit of 0.2% Au-doped In2O3 nanotubes (0.2% Au, mass fraction) is as low as 750 ppb. Meanwhile, the sensing material shows a response value of 18.2 to 50 ppm of CO at 240 °C, which is about 2.8 times higher than that of pure In2O3. Meanwhile, the response and recovery times are short (37 s/86 s). The gas-sensing mechanism of CO is uncovered by in situ DRIFTS through the reaction intermediates. In addition, first-principles calculations suggest that Au doping of In2O3 significantly enhances its adsorption energy for CO and improves the electron transfer properties. This study reveals a novel synthesis pathway for Au-doped In2O3 nanotubular structures and their potential application in low concentration CO detection.

Isoreticular Covalent Organic Pillars: Engineered Nanotubular Hosts for Tailored Molecular Recognition.

In the realm of nanoscale materials design, achieving precise control over the dimensions of nanotubular architectures poses a substantial challenge. In our ongoing pursuit, we have successfully engineered a novel class of single-molecule nanotubes─isoreticular covalent organic pillars (iCOPs)─by stacking formylated macrocycles through multiple dynamic covalent imine bonds, guided by principles of reticular chemistry. Our strategic selection of rigid diamine linkers has facilitated the synthesis of a diverse array of iCOPs, each retaining a homologous structure yet offering distinct cavity shapes influenced by the linker choice. Notably, three of these iCOP variants feature continuous one-dimensional channels, exhibiting length-dependent host-guest interactions with α,ω-dibromoalkanes, and each presenting a distinct critical guest alkyl chain length threshold for efficient guest encapsulation. This newfound capability not only provides a platform for tailoring nanotubular structures with precision, but also opens new avenues for innovative applications in molecular recognition and the purification of complex mixtures.

MoS2-Decorated Tubular Carbon Nanostructures with Enhanced Dielectric Loss for Boosting Microwave Absorption

MoS₂-Decorated Tubular Carbon Nanostructures with Enhanced Dielectric Loss for Boosting Microwave Absorption

Synthesis and photocatalytic activity of zinc-doped copper sulfide with porous nanotubes structures

Zinc-doped copper sulfide (Zn-doped CuS) particles were synthesized by a hydrothermal method in EG (EG) solutions of different concentrations. The results showed that the concentration of EG could regulate the structural morphology of Zn-doped CuS, and the Zn-doped CuS formed in pure EG had a porous nanotubular structure, and its photocatalytic degradation efficiency of methylene blue was as high as 96 % under visible light with good stability. SEM and TEM imaging confirmed that the diameter of the Zn-doped CuS with porous nanotubular structure was 100 nm, and the wall thickness was 30 nm. This study presents a strategy to enhance the photocatalytic activity and performance of CuS for environmental applications through EG concentration and zinc doping.

On the Use of Nanoparticles in Dental Implants.

Results obtained in physics, chemistry and materials science on nanoparticles have drawn significant interest in the use of nanostructures on dental implants. The main focus concerns nanoscale surface modifications of titanium-based dental implants in order to increase the surface roughness and provide a better bone-implant interfacial area. Surface coatings via the sol-gel process ensure the deposition of a homogeneous layer of nanoparticles or mixtures of nanoparticles on the titanium substrate. Nanotubular structures created on the titanium surface by anodic oxidation yield an interesting nanotopography for drug release. Carbon-based nanomaterials hold great promise in the field of dentistry on account of their outstanding mechanical properties and their structural characteristics. Carbon nanomaterials that include carbon nanotubes, graphene and its derivatives (graphene oxide and graphene quantum dots) can be used as coatings of the implant surface. Their antibacterial properties as well as their ability to be functionalized with adequate chemical groups make them particularly useful for improving biocompatibility and promoting osseointegration. Nevertheless, an evaluation of their possible toxicity is required before being exploited in clinical trials.

Ultrahigh Electrode Performance of Low‐Loaded Iridium Jagged Nanotubes for Water Electrolysis Applications

AbstractHighly active Ir electrocatalysts based on ultralow loading for proton exchange membrane water electrolysis (PEMWE) applications are desirable to achieve gigawatt production levels. However, no clear direction has been developed yet to achieve that scale. Here, newly‐synthesized Ir‐based jagged nanotubes (J‐IrNTs) with the ultrahigh electrode performance of 10 A mgIr−1 at 1.6 V in a PEMWE cell at Ir loadings as low as 0.05 mgIr cm−2 are reported, outperforming previously reported Ir‐based electrocatalysts. The Ir‐JrNT also exhibits only marginal degradation in stability tests. Notably, the resulting electrode of Ir‐JrNT provides enhanced intrinsic catalytic activity and high surface area for efficient electrocatalysis, with hierarchical branching composed of interconnected multiscale channels and highly corrugated surface textures, for facile mass transport. The findings demonstrate that the jagged nanotubular structure is a promising approach for overcoming the limitations associated with Ir‐based electrocatalysts and developing sustainable advanced PEMWE.

Porous Organic Nanotubes: Chemistry of One-Dimensional Space.

ConspectusOne-dimensional organic nanotubes feature unique properties, such as confined chemical environments and transport channels, which are highly desirable for many applications. Advances in synthetic methods have enabled the creation of different types of organic nanotubes, including supramolecular, hydrogen-bonded, and carbon nanotube analogues. However, challenges associated with chemical and mechanical stability along with difficulties in controlling aspect ratios remain a significant bottleneck. The fascination with structured porous materials has paved the way for the emergence of reticular solids such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic cages. Reticular materials with tubular morphology promise architectural stability with the additional benefit of permeant porosity. Despite this, the current synthetic approaches to these reticular nanotubes focus more on structural design resulting in less reliable morphological uniformity. This Account, highlights the design motivation behind various classes of organic nanotubes, emphasizing their porous interior space. We explore the strategic assembly of organic nanotubes based on their bonding characteristics, from weak supramolecular to robust covalent interactions. Special attention is given to reticular nanotubes, which have gained prominence over the past two decades due to their distinctive micro and mesoporous structures. We examine the synergy of covalent and noncovalent interactions in constructing assembly of these nanotube structures.This Account furnishes a comprehensive overview of our efforts and advancements in developing porous covalent organic nanotubes (CONTs). We describe a general synthetic approach for creating robust imine-linked nanotubes based on the reticular chemistry principles. The use of spatially oriented tetratopic triptycene-based amine and linear ditopic aldehyde building blocks facilitates one-dimensional nanotube growth. The interplay between directional covalent bonds and solvophobic interactions is crucial for forming uniform, well-defined, and high aspect ratio nanotubes. The nanotubes derive their permeant porosity and thermal and chemical stability from their covalent architecture. We also highlight the adaptability of our synthetic methodology to guide the transformation of one-dimensional nanotubes to toroidal superstructures and two-dimensional thin fabrics. Such morphological transformation can be directed by tuning the reaction time or incorporating additional intermolecular interactions to control the intertwining behavior of individual nanotubes. The cohesion of covalent and noncovalent interactions in the tubular nanostructures manifests superior viscoelastic mechanical properties in the assembled CONT fabrics. We establish a strong correlation between structural framework design and nanostructures by translating reticular synthesis to morphological space and gaining insights into the assembly processes. We anticipate that the present Account will lay the foundation for exploring new designs and chemistry of organic nanotubes for many application platforms.

Multiwalled carbon nanotubes supported Fe nanostructured interfaces for electrochemical detection of uric acid

Uric acid (UA) levels in biological fluids are an important diagnostic and prognostic biomarker for various metabolic disorders. Therefore, a convenient, facile, one-step electroreduction method to develop Fe nanostructured (FeNS) interfaces for highly sensitive electrochemical detection of UA. The synthesis process was thoroughly investigated at various deposition potentials, pH of the electrochemical bath solutions, and growth durations to attain excellent electrochemical response towards UA detection. The morphology and elemental composition of the FeNS/MWCNT were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS) techniques. We observed uniform deposition of FeNSs with sizes ranging from 100 − 120 nm on tubular nanostructures. The multiwalled carbon nanotubes supported Fe nanostructured interfaces (FeNS/MWCNT) generated at a potential of –1.1 V demonstrated excellent electrochemical response towards UA with a wide linear detection range of 5 to 500 µM with a sensitivity of 6.5605 µA µM−1 cm−2 and low detection limit of 3.26 µM. The excellent electrochemical response was attributed to the synergistic effect of MWCNTs, which facilitated FeNSs growth, leading to increased active sites for electrocatalysis and sensitive detection of UA. The convenience of the synthesis process, tunable electrochemical response, and reliability of the detection process make FeNS interfaces a potential option for developing electrochemical UA sensors.

Effect of current density on the morphology and electrochemical properties of nanotubular TiO2 for implant applications

This study focuses on investigating the influence of current density (i) (A/dm2) at values of 0.5 A dm−2, 1.0 A dm−2 1.5 A dm−2, and 2.0 A/dm2 on the surface structure of nanotubular titanium dioxide (TiO2) in an ethylene glycol solvent containing a certain amount of fluoride salt and water. The surface structure observed via FESEM images reveals that different current densities yield different nanotubular TiO2 structures, predominantly in the form of anatase TiO2 crystals. EIS and CV measurements indicate that at a current density of i = 1.5 A dm−2, the nanotubular TiO2 layer exhibits corrosion resistance performance up to 90.06% compared to the bare titanium (Ti) samples. Confocal laser scanning microscopy (CLSM) demonstrates enhanced attachment of BHK cells on anodized titanium surfaces compared to unmodified controls. These findings suggest that nanotubular TiO2 presents a biocompatible material with promising potential for biomedical implant applications.

Synthesis of Mesoporous Silica Using the Sol-Gel Approach: Adjusting Architecture and Composition for Novel Applications.

The sol-gel chemistry of silica has long been used for manipulating the size, shape, and microstructure of mesoporous silica particles. This manipulation is performed in mild conditions through controlling the hydrolysis and condensation of silicon alkoxide. Compared to amorphous silica particles, the preparation of mesoporous silica, such as MCM-41, using the sol-gel approach offers several unique advantages in the fields of catalysis, medicament, and environment, due to its ordered mesoporous structure, high specific surface area, large pore volume, and easily functionalized surface. In this review, our primary focus is on the latest research related to the manipulation of mesoporous silica architectures using the sol-gel approach. We summarize various structures, including hollow, yolk-shell, multi-shelled hollow, Janus, nanotubular, and 2D membrane structures. Additionally, we survey sol-gel strategies involving the introduction of various functional elements onto the surface of mesoporous silica to enhance its performance. Furthermore, we outline the prospects and challenges associated with mesoporous silica featuring different structures and functions in promising applications, such as high-performance catalysis, biomedicine, wastewater treatment, and CO2 capture.

On the Determination of Elastic Properties of Single-Walled Nitride Nanotubes Using Numerical Simulation.

In recent years, tubular nanostructures have been related to immense advances in various fields of science and technology. Considerable research efforts have been centred on the theoretical prediction and manufacturing of non-carbon nanotubes (NTs), which meet modern requirements for the development of novel devices and systems. In this context, diatomic inorganic nanotubes formed by atoms of elements from the 13th group of the periodic table (B, Al, Ga, In, Tl) and nitrogen (N) have received much research attention. In this study, the elastic properties of single-walled boron nitride, aluminium nitride, gallium nitride, indium nitride, and thallium nitride nanotubes were assessed numerically using the nanoscale continuum modelling approach (also called molecular structural mechanics). The elastic properties (rigidities, surface Young's and shear moduli, and Poisson's ratio) of nitride nanotubes are discussed with respect to the bond length of the corresponding diatomic hexagonal lattice. The results obtained contribute to a better understanding of the mechanical response of nitride compound-based nanotubes, covering a broad range, from the well-studied boron nitride NTs to the hypothetical thallium nitride NTs.

Nanostructured boron-doped diamond electrodes for two-electron water oxidation to produce hydrogen peroxide

Boron-doped diamond (BDD) electrodes have been widely used in water treatment, e.g., degradation of antibiotics and pigments for water purification. Hydrogen peroxide production by two-electron electrochemical oxidation of water is a green and attractive method that has the potential to replace the conventional anthraquinone autoxidation (AO) process. In this study, BDD films were prepared on single-crystal silicon wafers by using hot-filament chemical vapor deposition (HFCVD) technique. Then, dense tubular nanostructure (nanotubes) arrays were prepared on the BDD films employing inductively coupled plasma (ICP) etching. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) proved the formation of oxygen-terminated nanostructures, which was ascribed to the oxygen plasma and the self-masking. The length of diamond nanotubes as well as the root diameter increased gradually and non-linearly with the increase of etching time. It was indicated by cyclic voltammetry (CV) analysis that the effective active area of the electrodes increased after etching, and variations of resulting reaction performance were observed. The oxygen-terminated and nanostructured BDD electrode obtained by etching with the optimized parameters features better electrocatalytic performance, with reduced oxidation potential and 46.8 % higher Faraday Efficiency (FE) for hydrogen peroxide production, compared to the original BDD sample. Therefore, the manufacturing of nanostructures is an effective method to improve the efficiency of BDD water oxidation for the production of hydrogen peroxide.

Bioinspired Nanotubular Structures by Soft-Template Electropolymerization: 3,4-(2,3-naphtylenedioxy)Thiophene Monomers Quenched to Form Dimers

Preparing well-ordered nanotubes on materials surface is a great of interest in many applications. Bio-inspired and theoretical approaches show that porous structures such as nanotubes are key parameters for both surface hydrophobicity and water adhesion. Here, a very easy soft-template electropolymerization approach is used to form nanotubular structures, followed by a bioinspired strategy to control the wetting properties. Fully conjugated monomers based on 3,4-(2,3- naphtylenedioxy)thiophene (NaphDOT) core grafted with many rigid aromatic groups such as phenyl, naphthalene, pyrene, pyrrole, were synthesized. Then, electropolymerization is carried out with these monomers, followed by surface and morphologies characterization of corresponding polymers. We show that even if just dimers are formed by electropolymerization, the resulting polymer can be sufficiently insoluble to form structured films. 3,4-(2,3-naphtylenedioxy)thiophene (NaphDOT) is chosen as a judicious example, due to strong <i>π</i>-stacking interactions, and also their capacity to form nanotubular structures by soft template-electropolymerization in the presence of water (H<sub>2</sub>O). Here, different substituents, polymerizable or not, are grafted on the 2-position of thiophene. Films are formed with all the studied substituents. Nanotubular structures are especially observed with the following substituents: hydroxyl, pyrene and pyrrole, but in the presence of H<sub>2</sub>O. We study also their influence on the surface hydrophobicity.

TiO2 nanotubes immobilized on polyurethane foam as a floating photocatalyst for water treatment

We investigated the photocatalytic activity of TiO2 nanoparticles (TiO2-NPs) and TiO2 nanotubes (TiO2-NTs) supported on a floating polyurethane (PU) foam for removing Bisphenol A (BPA) as a model pollutant. We fabricated TiO2-NPs by the sol-gel method and TiO2-NTs by the ultrasound-assisted hydrothermal method. Subsequently, the photocatalysts were immobilized onto the PU foam through the wet chemical deposition process. The synthesized photocatalysts were characterized by contact angle, SEM-EDS, TEM, XRD, DRS, and BET analyses. TiO2-NPs and TiO2-NTs were successfully deposited onto the PU foam, creating floating photocatalysts denoted as TiO2-NPs@PU and TiO2-NTs@PU. Our findings indicated that the nanotubular structure of floating TiO2 photocatalysts enhanced the removal efficiency of BPA relative to the nanoparticles, resulting in the complete removal of the pollutant over 180 min of simulated sunlight irradiation. TiO2-NTs@PU was also stable after five reuse cycles. Moreover, h+ was the main scavenging reactive species during the photocatalysis of BPA with TiO2-NTs@PU.