Multifunctional TiO2 Research Articles

Synthesis and investigation of multifunctional TiO2 photocatalysts modified by metal nanoparticles

Photocatalysts based on the anodic single-walled titania nanotubes modified with metal nanoparticles (Au, Pd, Pt) were prepared and investigated. The metal nanoparticles sizes are in a range from 3 to 15 nm. The wall thickness of the nanotubes varied from 14 to 17 nm. It is established that photocatalysts with Au, Pd, Pt produce acetaldehyde during complete ethanol decomposition reaction. Additionally the formation of methane occurs in the TiO2 nanotubes with Pd and Au nanoparticles. We obtained firstly the multifunctional TiO2 nanotubes modified with Pd and Au nanoparticles for use both in air purification and in the production of hydrocarbon fuel precursors.

Effect of anodizing time on the structural color and photocatalytic properties of the TiO2 films formed by electrochemical method

Environmentally friendly materials are gaining more and more importance day by day. Structural colored materials without chemical pigments have become popular in this respect. It was aimed to produce structurally colored, photocatalytic TiO2 film coatings on the Titanium substrates using the anodizing method. Since the TiO2 structure, which has photocatalytic properties, is not covered with any coating such as paint, the function of cleaning the environment with solar energy is preserved. The crystallite sizes of the anatase and rutile phases were found between 22.18 and 22.18 nm. The highest photocatalytic efficiency was obtained at the sample anodized for 60 s with 60% efficiency. The surface morphologies of the samples were transformed into a worm-like morphology after anodization for 600 s. These regular indentations of the worm-like structure create extra coherent light scattering in the red region, similar to the photonic crystal surfaces. So, the main outcome is that the obtained colors can be controlled by Photonic Crystal morphologies. Also, extremely eco-friendly, multifunctional TiO2 film coatings with both structural color and photocatalytic properties were obtained.

Synergistic antibacterial effect of multifunctional TiO2−X-based nanoplatform loading arginine and polydopamine for promoting infected wounds healing

The gas therapy of some endogenous signaling molecules to treat diseases has caused extensive research, among which NO gas has shown great potential in fighting infection with various pathogens, promoting wound healing, etc. Here, we propose a photothermal/photodynamic/NO synergistic antibacterial nanoplatform by loading L-arginine (LA) on mesoporous TiO2 and then encapsulating it with polydopamine. The obtained TiO2−x-LA@PDA nanocomposite possesses both the excellent photothermal effect and ROS generation ability of mesoporous TiO2, and the release of nitric oxide (NO) from L-arginine under near-infrared (NIR) light irradiation, while the sealing layer of PDA could induce NIR-triggered NO controlled release. In vitro antibacterial experiments confirmed that the synergistic effect of TiO2−x-LA@PDA nanocomposites has excellent antibacterial effects against Gram-negative and Gram-positive bacteria, while in vivo experiments showed that it has lower toxicity. It is worth noting that compared with the pure photothermal effect and ROS, the generated NO showed a better bactericidal effect, and NO had a better ability to promote wound healing. In conclusion, the developed TiO2−x-LA@PDA nanoplatform can be used as a nanoantibacterial agent, which can be further explored in the related biomedical field of photothermal activation of multimodal combined antibacterial therapy.

Zr-doped TiO2 ceramic nanofibrous membranes for enhancing photocatalytic organic pollutants degradation and antibacterial activity

Titanium dioxide (TiO2) is well known for its photocatalytic and antibacterial properties which are widely used in organic pollutants treatment and antibacterial. However, the fast recombination of electron-hole pairs of TiO2 and the wide bandgap energy during photocatalysis progress are prominently degrades its photocatalytic efficiency. In this study, we designed and investigated Zr-doped TiO2 ceramic nanofibrous membranes with enhanced photocatalytic properties for dye scavenging and bacteria inactivation. A mixture solution of poly(acrylonitrile) (PAN) and preceramic polymers (Zr-doped polytitanoxane) was electrospun to fabricate Zr-doped TiO2 ceramic nanofibrous membranes, which were then carbonized in argon at 600 °C and calcined in air at 400 °C. It was found that the morphologies, structures, and characteristics of ceramic nanofibrous membranes were significantly influenced by the composition and content of preceramic polymers. The doping of Zr element improved photocatalytic activity of ceramic nanofibrous membranes and achieved efficient antibacterial activity. This work demonstrates a new strategy for the fabrication and application of multifunctional TiO2 composites by incorporating with ceramic nanofibrous membranes.

The Antibacterial and Hydrophobic Cotton Fabrics Constructed by Multifunctional Polysiloxane and TiO2 Nanoparticles

The Antibacterial and Hydrophobic Cotton Fabrics Constructed by Multifunctional Polysiloxane and TiO2 Nanoparticles

Unique kinetics feature and excellent photocatalytic performance of tetracycline photodegradation using yolk-shell TiO2@void@TiO2:Eu3+

The multifunctional yolk-shell TiO2 @void@TiO2:Eu3+ calcined at different temperatures were successfully fabricated by sacrificial template method for the photodegradation of tetracycline. The impacts of yolk-shell and calcination temperature on the photoluminescence and photocatalytic properties have been investigated in detail. The photoluminescence results show that sample calcined at 800 °C exhibits the strongest red emission. The photocatalytic efficiency for tetracycline reached 90.34 % in 50 min at 20 mg/L TC solution by sample calcined at 900 °C. The kinetics fitting curves is with different slopes, which is reported for the first time so far. Meanwhile, the photocatalytic mechanism and possible photodegradation pathway of tetracycline were proposed. Compared with the double-shell samples, the yolk-shell samples show a high photodegradation rate within 5 min and unique kinetics feature. The analysis of photocatalytic kinetics provides a new idea for studying the photocatalysis mechanism. The rapid tetracycline photodegradation by the yolk shell material also provides new strategies for practical water purification.

Multifunctional TiO2 coatings developed by plasma electrolytic oxidation technique on a Ti20Nb20Zr4Ta alloy for dental applications.

A newly developed β-Ti alloy based on the Ti-Nb-Zr-Ta system (Ti20Nb20Zr4Ta) has been subjected to Plasma Electrolytic Oxidation (PEO) treatment to obtain a multifunctional ceramic-like (TiO2) coating with superior tribocorrosion (wear and corrosion) resistance and improved biocompatibility. For this aim, elements such as Ca, P, and Ag NPs have been incorporated into the oxide film to obtain bioactive and biocide properties. The chemical composition and morphology of the TiO2-PEO coating was characterized, and its multifunctionality was addressed by several means, including antibacterial activity assessment, formation of bone-like apatite, metallic ion release evaluation, in vitro cellular response analysis, and corrosion and tribocorrosion tests in artificial saliva. The developed coatings enhanced the corrosion and tribocorrosion resistance of the bare alloy and exhibited antibacterial ability with low cytotoxicity and negligible ion release. Furthermore, they were able to sustain MC3T3-E1 preosteoblast viability/proliferation and osteogenic differentiation. Altogether, the results obtained demonstrate the potential of the TiO2 coating incorporating Ca, P, and Ag NPs to be used for dental applications.

Efficient design and optimization of multifunctional N-F-TiO2/rGO films via orthogonal composite approach

An orthogonal composite approach is proposed to study the multielement synergistic modified TiO2 photocatalytic films. The relationship between different preparation factors and photocatalytic evaluation indexes including photo-degradation activities, antibacterial properties, light transmittance and hydrophilicity, is revealed by the correlation and difference analysis. The increase of F content improves the photocatalytic and antibacterial activities. While the increase of Fe content and calcination temperature are not conducive to the transmittance. Additionally, reduced graphene oxide (rGO) is beneficial to improve the antibacterial properties, but it is not conducive to the self-cleaning performance. The interaction between different factors cannot be ignored in the design of multifunctional TiO2 films from Pareto analysis. The optimal state shows that the glass coated with multifunctional F(9%)-N(1%)-TiO2/rGO(0.5%)-300 ℃ film exhibits the highest photo-degradation (59.8%) and antibacterial activities (87.1%) with superior transmittance (84.1%) and hydrophilicity (7.0°) under visible-light irradiation condition.

A Novel High-Performance TiO2-x /TiO1-y Ny Coating Material for Silicon Anode in Lithium-Ion Batteries.

Protective surface coatings on Si anodes are promising for improving the electrochemical performance of lithium-ion batteries (LIBs). Nevertheless, most coating materials have severe issues, including low initial coulombic efficiency, structural fracture, morphology control, and complicated synthetic processing. In this study, a multifunctional TiO2- x /TiO1- y Ny (TTN) formed via a facile and scalable synthetic process is applied as a coating material for Si anodes. A thin layer of amorphous TiO2 is uniformly coated onto Si nanoparticles by a simple sol-gel method and then converted into a two phase TiO2- x /TiO1- y Ny via nitridation. The lithiated TiO2-x provides high ionic and electrical conductivity, while TiO1-y Ny can improve mechanical strength that alleviates volume change of Si to address capacity fading issue. Owing to these synergetic advantages, TiO2- x /TiO1- y Ny -coated Si (Si@TTN) exhibits excellent electrochemical properties, including a high charge capacity of 1650mAhg-1 at 0.1Ag-1 and 84% capacity retention after 100 cycles at 1Ag-1 . Moreover, a significantly enhanced rate performance can be achieved at a high current density. This investigation presents a facile and effective coating material to use as the high-capacity silicon anode in the emerging Si anode technology in LIBs.

Fabrication and characterization of multifunctional nanoclay and TiO2 embedded polyamide electrospun nanofibers and their applications at indoor air filtration

The multifunctional polyamide-6 (PA-6) electrospun nanofibers were fabricated for indoor air filtration. Nanoclay (NC) was used as nanoadsorbent, and TiO2 was preffered as nanocatalyst for photocatalytic oxidation of toluene. The main responses of study were selected as characterization (fiber diameter, tensile strength, air permeability and water vapor transmission) and performance parameters (adsorption and oxidation of toluene). These parameters of nanofibers ranged from 75.8 to 135.9 nm for fiber diameter, 0.51–3.47 MPa for tensile strength, 11.6–19.0 mm/sn for air permeability, 119.9–309.4 g/m2.h for water vapor permeability, 7.0%-43.7% adsorption efficiency at 15 min, and 7.4–12.6% oxidation efficiency at 66 min. The increase in NC content decreased the air permeability values and increased the tensile strength values of nanofibers. The adsorption efficiencies of nanofibers increased from 7% to 28.9, 35.3 and 43.7% with increasing NC ratios (0.0–0.025–0.05–0.5%). The highest CO2 production was obtained for nanofiber having 0.05% of NC and 1% of TiO2 at low UV light energy and short filtration time.

Toward high‐efficiency stable 2D/3D perovskite solar cells by incorporating multifunctional CNT:TiO2 additives into 3D perovskite layer

AbstractThe power conversion efficiency (PCE) of 2D/3D perovskite solar cells (PSCs) is still significantly low compared with 3D PSCs due to the poor charge transport ability of 2D perovskite thin films and a large number of defects in 3D thin films. Herein, to address these two issues, multifunctional TiO2 nanoparticles (NPs)‐modified carbon nanotubes (CNT:TiO2) additives are incorporated into 3D perovskite layer for the first time, and demonstrate three positive effects for CNT:TiO2 material application: firstly, it passivates the defect state of the 3D perovskite layer and enhances the charge mobility of the 3D layer; secondly, its interaction with the 2D film increases the conductivity of the 2D layer and produces the interface polarization electric field to promote the hole extraction. As a consequence, not only the PCE of the optimized 2D/3D PSCs with the CNT:TiO2 is greatly improved to 22.7% from 19.8% of the control PSCs, but also the stability is significantly improved.image

Photoelectrochemical IL-6 Immunoassay Manufactured on Multifunctional Catecholate-Modified TiO2 Scaffolds.

There is an increasing interest in using photoelectrochemistry for enhancing the signal-to-noise ratio and sensitivity of electrochemical biosensors. Nevertheless, it remains challenging to create photoelectrochemical biosensors founded on stable material systems that are also easily biofunctionalized for sensing applications. Herein, a photoelectrochemical immunosensor is reported, in which the concentration of the target protein directly correlates to a change in the measured photocurrent. The material system for the photoelectrode signal transducer involves using catecholate ligands to modify the properties of TiO2 nanostructures in a three-pronged approach of morphology tuning, photoabsorption enhancement, and facilitating bioconjugation. The catecholate-modified TiO2 photoelectrode is combined with a signal-off direct immunoassay to detect interleukin-6 (IL-6), a key biomarker for diagnosing and monitoring various diseases. Catecholate ligands are added during hydrothermal synthesis of TiO2 to enable the growth of three-dimensional nanostructures to form highly porous photoelectrodes that provide a three-dimensional scaffold for immobilizing capture antibodies. Surface modification by catecholate ligands greatly enhances photocurrent generation of the TiO2 photoelectrodes by improving photoabsorption in the visible range. Additionally, catecholate molecules facilitate bioconjugation and probe immobilization by forming a Schiff-base between their -COH group and the -NH2 group of the capture antibodies. The highest photocurrent achieved herein is 8.89 μA cm-2, which represents an enhancement by a factor of 87 from unmodified TiO2. The fabricated immunosensor shows a limit-of-detection of 3.6 pg mL-1 and a log-linear dynamic range of 2-2000 pg mL-1 for IL-6 in human blood plasma.

Multifunctional CNT:TiO2 additives in spiro‐OMeTAD layer for highly efficient and stable perovskite solar cells

AbstractHole transport layer (HTL) is very important for the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). As current state‐of‐the‐art HTL, Li‐TFSI doped spiro‐OMeTAD often suffers low conductivity and the hydrolysis of the additive Li‐TFSI, which significantly hinders the further improvement of PCE of PSCs. Besides, conventional spiro‐OMeTAD has no functional of directly passivating the perovskite crystal defects. Herein, multifunctional TiO2 nanoparticles (NPs)‐modified CNT (CNT:TiO2) doped spiro‐OMeTAD (spiro‐OMeTAD+CNT:TiO2) HTL is reported for the first time. The incorporated CNT:TiO2 not only significantly increases the conductivity of spiro‐OMeTAD+CNT:TiO2, but also effectively passivates the crystal defects of perovskite layer. The optimized PSCs with spiro‐OMeTAD+CNT:TiO2 HTL achieved a peak PCE of 21.53%, much higher than that (17.90%) of the conventional spiro‐OMeTAD based PSCs and also show significantly improved stability.image

Formation of multi-functional TiO2 surfaces on AA2024 alloy using plasma electrolytic oxidation

Plasma electrolytic oxidation (PEO) was applied to functionalise the surface of AA2024 alloy. A potassium titanium-oxide oxalate dihydrate based aqueous electrolyte was used, which allowed the direct formation of a TiO2 surface layer on the aluminium alloy substrate. The effect of PEO treatment time and the additional presence of anatase particles in the electrolyte solution on the surface layer and its properties (corrosion, wear and photocatalytic activity) were investigated.It was found that the coating thickness and surface morphology are strongly dependent on the PEO processing time. However, the phase composition is not much affected by the treatment time and the main coating phase is rutile with a smaller amount of anatase. Adding additional anatase in the form of particles increases the amount of anatase in the coatings. The additional particle addition has only minor effect on the corrosion resistance, but reduces the wear resistance remarkably. Interestingly, the addition of anatase particles and the PEO treatment time are not effective in increasing the photocatalytic activities of the samples.

Mehanske in strukturne lastnosti večfunkcionalnega oksidnega nanosa na osnovi TiO2, izdelanega z atmosferskim plazemskim naprševanjem

Mehanske in strukturne lastnosti večfunkcionalnega oksidnega nanosa na osnovi TiO2, izdelanega z atmosferskim plazemskim naprševanjem

Reaction induced multifunctional TiO2 rod/particle nanostructured materials for screen printed dye sensitized solar cells

This study investigates the potential of utilizing multifunctional nanostructured materials for the efficient light trapping and electron transport in solar cells by combining titanium dioxide (TiO2) rods and nanoparticles. A simple solvothermal method was adopted for the synthesis of coupled morphology adopting the desired precursor with the constant concentration and temperature. The reaction duration (12, 24, 36 and 48 h) was varied and the materials resultant physical, optical and structural characteristics were elucidated to determine the nature of the prepared material. The crystallographic phase of the synthesized samples was determined with XRD and Raman analysis. From the experimental data it is hypothesized that the surface plane of anatase (105) is involved in the deformation of the structure and the formation of the rutile phase. To further investigate on the formation of mixed phase in the prepared sample a computation study was performed using density functional theory coupled to the Hubbard U correction (DFT + U) as a function of volume in both the anatase and rutile phases. The relative stability of the O–Ti–O networks is explored starting from ultrathin materials for four different sizes, of anatase and rutile nanorods separately. Finally, the synthesized TiO2 materials were used to prepare screen printed dye sensitized solar cell (DSSC) devices and their respective properties were quantified.

Photo-functionalized TiO2 nanotubes decorated with multifunctional Ag nanoparticles for enhanced vascular biocompatibility

Titanium dioxide (TiO2) has a long history of application in blood contact materials, but it often suffers from insufficient anticoagulant properties. Recently, we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties. However, for long-term vascular implant devices such as vascular stents, besides anticoagulation, also anti-inflammatory, anti-hyperplastic properties, and the ability to support endothelial repair, are desired. To meet these requirements, here, we immobilized silver nanoparticles (AgNPs) on the surface of TiO2 nanotubes (TiO2-NTs) to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties. The photo-functionalized TiO2-NTs showed protein-fouling resistance, causing the anticoagulant property and the ability to suppress cell adhesion. The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property. The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property, a strong inhibitory effect on smooth muscle cells (SMCs), and low toxicity to endothelial cells (ECs). The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs, and therefore has enormous potential in the field of cardiovascular implant devices. Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility.

Screen printed multifunctional TiO2 photoanode with plasmonic Ag nanoparticles for performance enhancement of dye sensitized solar cell

Multifunctional TiO2 powder consisting of solid microspheres/nanoparticles (NPs) was obtained in single step hydrothermal method. The insights of mesoporous solid TiO2 microspheres are observed as interconnected particles granules in the field emission scanning electron microscope (FESEM) investigation. Secondly, Ag nanoparticles (AgNPs) of spherical shaped with narrow size distribution was synthesised by reduction process and its extinction maximum at 413 nm was observed from UV–Vis analysis. Screen printed TiO2 photoanode containing plasmonic AgNPs was utilised to construct the dye sensitized solar cell (DSSC). The efficiency and optical properties of the bare and plasmonic devices were compared. Noticeable improvement in device efficiency is attributed to plasmonic properties of the incorporated AgNPs.

A novel rutile TiO2/AlPO4 core-shell pigment with substantially suppressed photoactivity and enhanced dispersion stability

Decorating inorganic particles with core-shell structure is an attractive approach to broaden their practical application owing to the synergistic effects between inner core and outer shell. In this work, a novel rutile TiO2@AlPO4 core-shell composite has been constructed via a facile one-step wet chemical deposition method. The dense and thick AlPO4 shell can hinder direct contact between TiO2 core and outer environment, decrease light absorption ability, suppress separation of electron-hole pairs, and accelerate electron annihilation. Such unique properties hindered the generation of reactive oxygen species, further contributing to the suppression of photoactivity. The superior dispersion stability in aqueous system of TiO2@AlPO4 core-shell hybrid was attributed to its enhanced surface electronegativity. Thus-produced TiO2@AlPO4 core-shell hybrid with suppressed photoactivity and enhanced dispersion stability could further increase the weather durability and prolong the life span of TiO2-based pigment. Overall, this study provides new insight into the mass production of multi-functional rutile TiO2 pigments.

Bioinspired multifunctional TiO2 hierarchical micro/nanostructures with tunable improved bone cell growth and inhibited bacteria adhesion

Two main origins of failure for hard tissue replacements are structural loosening and prosthetic implant infections (PIIs). Bioinspired multifunctional TiO2 hierarchical micro/nanostructures of conical-shaped TiO2 (CTO), regular TiO2 nanotubes (RTO) and irregular TiO2 nanotubes (ITO) with tunable improved cell growth and inhibited bacteria adhesion were synthesized. CTO and ITO samples indicated superhydrophilicity with contact angles of less than 5°. The MTT assay demonstrated excellent biological performance for RTO and CTO sample with 98.1% and 103.1% of cell viability, respectively. The bridging force for osteoblast cell attachment onto the synthesized porous coatings was presented as a possible mechanism. Ultimately, effect of different synthesized surfaces on both Gram-negative, Esherichia coli, and Gram-positive, Staphylococcus aureus, bacteria were estimated. The number of both Gram-negative and Gram-positive bacteria per field (NBPF) for RTO were calculated 31 and 42 respectively which were reduced more than approximately 7 and 6 times compared to the calculated NBPF of 222 and 258 for the untreated RT substrate. The recommended approach for bacteria adhesion inhibition without using antibiotics presents an auspicious solution to counteracting bacterial resistance to antibiotics.