Morphology Of TiO Research Articles

The LSPR regulation of TiO2: W nanocrystals and its application in enhanced upconversion luminescence

The localized surface plasmon resonance (LSPR) absorption peaks of semiconductor nanocrystals are mainly concentrated in the infrared band, and the absorption characteristics can be controlled by the amount of element doping. The coupling of upconversion nanocrystals (UCNPs) and semiconductor nanocrystals can improve the upconversion luminescence (UCL) of rare-earth ions. Here, the LSPR absorption and morphology of the semiconductor nanocrystalline TiO2: W were adjusted by using ammonium fluoride during synthesis. Significant absorption enhancement of TiO2: W in the near-infrared region was obtained to enhance the UCL of NaYF4: Yb3+, Er3+. The Glass/NaYF4: Yb3+, Er3+/TiO2: W@SiO2 layered structure films were fabricated through spin coating. Compared with Glass/NaYF4: Yb3+, Er3+, the green and red lights of the Glass/NaYF4: Yb3+, Er3+/TiO2: W@SiO2 films were enhanced by 15.9 and 17.8 times, respectively. The UCL enhancement of Glass/NaYF4: Yb3+, Er3+/TiO2: W@SiO2 was derived from the LSPR property of TiO2: W through the enhancement of the excitation. The present work is important for possible applications of these layered structures as biomarkers, photocatalysts, flexible materials, and photoluminescence display panels.

Magnesium doped TiO2 as an efficient electron transport layer in perovskite solar cells

Perovskite solar cells (PSCs) are rapidly emerging as efficient solar cells due to the efficient photovoltaic and physiochemical properties. Ideally, the absorber layer in PSCs is sandwiched between highly conductive electron transport layer (ETL) and highly stable hole transport layer (HTL). The interfaces between these layers highly affect the performance of PSCs. In this study Magnesium (Mg) doped TiO2 based ETL is systematically investigated to enhance the optical and morphological properties of the layer and the interface. It was observed that with Mg doping in mesoporous TiO2, morphology of TiO2 based ETL film was significantly improved thereby providing an interface for the growth of absorber layer. Optoelectronic studies suggested that band gap was effectively reduced with the addition of Mg and absorption range was also enhanced. Electrical analysis yielded, Mg doped TiO2 based ETL showed enhanced conduction and better sheet carrier mobility as compared to undoped films. Thermal studies indicate fabrication of a thermally stable ETL material for PSCs. Moreover, Current density-Voltage (J-V) measurements indicated more than two-fold increase in photovoltaic efficiency of 3 wt% Mg.

Microwave Plasma Assisted Sol‐Gel Synthesis of TiO2 Photocatalyst for DC Plasma Jet Driven Degradation of Methylene Blue

AbstractA new microwave plasma assisted sol‐gel (MPAS) technique was adopted to produce Titanium dioxide (TiO2) photocatalyst by using pure and mixed stabilizers. The crystalline phases, composition, bandgap energy and surface morphology of TiO2 were studied through SEM, XRD, FT‐IR, UV‐Visible spectroscopy and photoluminescence spectroscopy. The average particle size of MPAS synthesized TiO2 nanoparticles remained smaller than the simple sol‐gel method while bandgap energy increased by 40 %. The rutile content and crystallinity of nanoparticles were also found higher in MPAS synthesized TiO2 than the simple sol‐gel method. The type of stabilizer only effected the particle size but not the phase transformations of TiO2 nanoparticles. TiO2 photocatalyst with band gap of 3.06 eV was used to degrade methylene blue dye in water under the exposure of open atmosphere argon plasma jet. UV radiation intensity of the plasma jet at a distance of 2 cm was 576 μW/cm2, which reduced to 149 μW/cm2 at 10 cm. The plasma jet produced some highly reactive species and UV radiations. The reactive species reacted with dye molecules while UV radiations promoted the activity of TiO2. The dye degradation efficiency of the process, under the combined effect of reactive species and TiO2 activity, reached to 95 % after 30 min of plasma exposure time.

A photoanode with hierarchical nanoforest TiO2 structure and silver plasmonic nanoparticles for flexible dye sensitized solar cell

Due to unique photovoltaic properties, the nanostructured morphologies of TiO2 on flexible substrate have been studied extensively in the recent years for applications in dye sensitized solar cells (DSSCs). Microstructured electrode materials with high surface area can facilitate rapid charge transport and thus improve the light-to-current conversion efficiency. Herein we present an improved photoanode with forest like photoactive TiO2 hierarchical microstructure using a simple and facile hydrothermal route. To utilize the surface plasmon resonance (SPR) and hence increase the photon conversion efficiency, a plasmonic nanoparticle Ag has also been deposited using a very feasible photoreduction method. The branched structure of the photoanode increases the dye loading by filling the space between the nanowires, whereas Ag nanoparticles play the multiple roles of dye absorption and light scattering to increase the light-to-current conversion efficiency of the device. The branched structure provides a suitable matrix for the subsequent Ag deposition. They improve the charge collection efficiency by providing the preferential electron pathways. The high-density Ag nanoparticles deposited on the forest like structure also decrease the charge recombination and therefore improve the photovoltaic efficiency of the cells. As a result, the DSSC based on this novel photoanode shows remarkably higher photon conversion efficiency (ηmax = 4.0% and ηopt = 3.15%) compared to the device based on pristine nanowire or forest-like TiO2 structure. The flexibility of the device showed sustainable and efficient performance of the microcells.

Study of Ag2O/TiO2 nanowires synthesis and characterization for heterogeneous reduction reaction catalysis of 4-nitrophenol

Ag2O/TiO2 nanowires as catalyst for reduction reaction of 4-nitrophenol has been synthesized in this study with molten-salt route and followed by the impregnation method. Analysis by characterization results show that the addition of Ag2O does not change TiO2 crystal structure and morphology, and it was found that the impregnated Ag2O has metal-support interactions with TiO2 nanowires. Size distribution of TiO2 nanowires structure along with the Ag2O is known to be within the range of nanomaterial. TiO2 nanowires has an average width of 339.706 nm, and the impregnated Ag2O has an average diameter size of 19.873 nm respectively. The catalytic test performance shows that Ag2O/TiO2 nanowires has excellent result compared to the control sample morphology of Ag2O/TiO2 anatase. It is closely correlated with the electron transfer capability of TiO2 nanowires structure and this shows that Ag2O/TiO2 nanowires is suitable for catalysis of 4-nitrophenol reduction reaction.

Effects of the surface of solar-light photocatalytic activity of Ag-doped TiO2 nanohybrid material prepared with a novel approach

Surface modification with a nanomaterial has been confirmed to be an effective strategy to enhance the visible-light photodegradation efficiency of titanium dioxide nanoparticles (TiO2-NPs). In this regard, we used silver as an additive into TiO2-NPs to improve their photodegradation activity under visible light irradiation. Here, a novel and eco-friendly process was developed to prepare the Ag-doped TiO2 nanohybrid and named as photon-induced method (PIM). The XRD technique showed that the prepared Ag-doped TiO2 has mixed phases of anatase and rutile. However, the rutile-only phase was detected for the pure TiO2-NPs at 700 °C of calcination. Ultraviolet–visible (UV–Vis) absorption spectra revealed a reduction in the energy bandgap of TiO2 after Ag doping. Besides, the addition of Ag resulted in a significant improvement of TiO2 morphology. Methylene blue (MB) dye was chosen to be an organic target to investigate the photocatalyst activity of the TiO2-NPs. In this regard, the degradation rate of MB was found to be 100% for the Ag-doped TiO2, which is higher than that of pure rutile TiO2. The incorporation of Ag additive plays a significant role in the improvement of TiO2 stability and photodegradation performance due to the surface plasmon resonance phenomenon.

Stability studies of hybrid TiO2 based nanofluids

This article studies the stability of hybrid TiO2 based nanofluid by varying the ultra-sonication time, weight fraction between carbon and TiO2 and type of surfactant. The objective of this research are synthesise volume fraction of 0.1% C - TiO2 hybrid nanofluid with 15ml of distilled water and study the effect of weight fraction between C and TiO2, type of surfactant and ultra-sonication time to the stability of hybrid nanofluid. Weight fraction between C – TiO2 will be varied at 0% - 100%, 10% - 90%, 50% - 50%, 90% - 10% and 100% - 0%. Different ultrasonication time will be used which are 1, 3 and 5 hours to determine the optimum ultrasonication time for the hybrid nanofluid. Sodium dodecyl sulphate (SDS) and Triton X-100 will be added into hybrid nanofluid to determine the effect of surfactant to the stability of hybrid nanofluid. The morphology and particle size characteristic of TiO2 and carbon powder is evaluated by using X-ray diffraction and FESEM. It is shown that TiO2 has particle size of around 30nm while carbon powder used is flat shaped. In this research, two steps method is used to synthesise the hybrid nanofluid. After mixing the two powder together, it will be mixed with distilled water by magnetic stirring for 3 hours. Then ultrasonication is included in synthesise of hybrid nanofluid to prevent agglomeration of particles. The pH values of each hybrid nanofluid is measured by using pH meter. Two stability evaluations are carried out which are centrifugation and zeta potential measurement. Centrifugation is carried out right after hybrid nanofluid is done ultra-sonicated for 30 minutes at 2000 RPM. Hybrid nanofluid that is ultra-sonicated for 3 hours resulted to achieve highest stability with highest value of zeta potential of -21.8 mV. 100% C - 0% TiO2 hybrid nanofluid has the highest zeta potential measurement of -37.6 mV. Finally, for type of surfactant, SDS able to enhance stability of hybrid nanofluid more than Triton X-100. The zeta potential of hybrid nanofluid after addition of SDS reached -47.0 mV which is higher than Triton X-100 which only achieve zeta potential measurement of -24.3 mV.

Synthesis and Characterization of Amorphous TiO2 Anode Prepared by Anodizing Method for Na-ion Batteries

Sodium ion battery (SIB) has engage sustainable alternative on replacing lithium ion batteries. The lower potential and larger ionic value has demanded on seeking a potential anode materials. Amorphous TiO2 prepared by electrochemical anodisation technique has provide a suitablility as anode SIB materials, which approved by conducting XRD, FTIR, and SEM-EDX measurements. Electrochemical performance was tested with variations in the concentration of NaOCl4 electrolyte in propylene carbonate (PC) solvent. Diffractogram of TiO2 showed the only peaks of Ti was observed at 2θ = 40.34. The TiO2 IR spectrogram shows that the absorption band at 507 cm-1 is the peak of the vibration characteristics of the Ti-O bond and the peak of 975 cm-1 corresponds to Ti-O-Ti bond. SEM-EDX image analysis showed the morphology of TiO2 was smooth without pore with a ratio of Ti: O elemental composition of 1: 2. Voltammogram showed the anodes in 0.5 M NaOCl4 electrolyte in PC solvent has a good stability potential windows with the high current density 1.2 mA and the capacity of 0.037 F/g

Construction of Fe2O3 loaded and mesopore confined thin-layer titania catalyst for efficient NH3-SCR of NOx with enhanced H2O/SO2 tolerance

TiO2 is a famous support for selective catalytic reduction of NO with NH3 (NH3-SCR). Engineering the morphology and structure of TiO2 is effective to modulate the interaction with surface dispersed component, providing further opportunity to improve catalytic performance. In this study, we rationally construct thin-layered titania confined in mesoporous silica via a surface grafting strategy. It exhibits high specific surface area with amorphous structure along mesopore channel, and much more Brønsted acid sites are generated than bulk TiO2 due to defect induced oxygen-related species. After iron oxide loading, both the denitration activity and H2O/SO2 tolerance are greatly promoted as compared to conventional Fe/TiO2. Further characterizations reveal the obtained catalyst displays uniform iron oxide dispersion and intense Fe-Ti interaction, resulting in superior redox behavior and increased acidity. Notably, it is found the introduction of H2O exhibits a promotional effect on NO conversion efficiency, which can be ascribed to enhancement of NH3 adsorption capability. Besides, SO2 has negligible disturbance on NO/NH3 adsorption, leading to superior sulfur tolerance. The result of present study demonstrates vital role of surface structure engineering of TiO2 for sustainable denitration, which opens up a new avenue for designing well-performed and stable NH3-SCR catalysts.

Development of optimized triaxially electrospun titania nanofiber‐in‐nanotube core‐shell structure

AbstractOne dimensional (1D) nanostructures and its derivatives can be manipulated to serve special functions like hollow structure, and higher surface area. 1D TiO2 nanotube‐in‐nanofibers (NF@NT) are developed through triaxial electrospinning followed by a calcination process. A blended solution of polyvinyl pyrrolidone and tetra‐butyl titanate is used in outer and inner layers of nanofibers, respectively, while paraffin oil is used in the middle layer. The optimized triaxial nanofibers of 669.4 ± 52.43 nm are developed at 7.5 w/w% concentration, 28 kV applied voltage, and 24 cm spinning distance. TiO2 NF@NT structure is obtained through calcination of optimized triaxial nanofibers at 550°C. Subsequently, the morphology of TiO2 NF@NT and its uniform diameter distribution is confirmed through scanning electron microscopy. Fourier‐transform infrared spectroscopy results indicates the formation of TiO2 NF@NT. X‐Rays diffraction pattern peaks also reveals the presence of both anatase and rutile crystalline phases. The presence of only titanium (Ti) and oxygen (O) elements in the TiO2 NF@NT is confirmed through energy dispersive X‐ray spectroscopy. Brunauer–Emmett–Teller analysis indicates that TiO2 NF@NT has a higher specific surface area of ~141.68 m2/g compared with the solid TiO2 nanofiber (~75.31 m2/g). This study can be adopted to develop TiO2 NF@NT for wide range of application.

Free-standing nitrogen-doped TiO2 nanorod arrays with enhanced capacitive capability for supercapacitors

TiO2 nanomaterials have attracted desirable attention as advanced electrode materials in supercapacitors, but they suffer from poor conductivity and low capacitance. Herein, we developed an effective approach to dramatically boost the capacitive capability of TiO2 nanorods by controlling the morphology of TiO2 and introducing N dopants upon nitridation process. The nitrided TiO2 with different morphologies are facilely synthesized by a seed-assisted hydrothermal method with different concentrations of nanosize TiO2 as seeds and subsequent nitridation. Without seeding, TiO2 nanorods are assembled into porous microflowers, while the introduction of seeds can induce the vertical growth of TiO2 nanorods. The results also show that the morphology of TiO2 can affect the doping degree of nitrogen. Owing to the improved charge transport and unique free-standing nanorod structure, the optimized nitrided TiO2 electrode obtains a remarkable areal capacitance of 177.1 mF cm−2 at 4 mA cm−2, which is much larger than nitrided TiO2 electrode without seeding (16 mF cm−2). This provides a general method for increasing the areal capacitance of nanomaterials by adjusting the seed solution concentration of the seed-assisted method.

Modification of morphology and optic properties of TiO2 as photoreforming catalyst for H2 production from biomass derivatives: a review

Hydrogen is one of the solutions to overcome the problems facing the world today, the energy crisis and a decrease in environmental quality. Its has high chemical energy per mass and its combustion only results water and does not emit greenhouse gas. Nevertheless, hydrogen doesn’t exist in nature as H2 form. Hence, it requires a sustainable production methods. Biomass (lignocellulose) and its derivatives can be renewable feedstock for producing biohydrogen via clean process i.e photoreforming. One of the keys to the success of this technology is the development of suitable photocatalysts that are able to maximize light harvesting from solar and hydrogen production. TiO2 is the establish material because of its high photocatalytic activity, not toxic, biologically and chemically inert. Its main drawback are its band gap value (ca. 3.2 eV) and fast recombination of electron–hole that detrimental to the photocatalytic activity. The alternative to overcome these problems are modification of TiO2 by nanotubes structure and doping of metals. In this paper, we will review about TiO2 nanotubes and its preparation strategies. Then, we will describe role of metal to enhance photocatalytic performance of TiO2 nanotubes. The Impact of both modification to morphology and optic properties and enhancement of H2 production from biomass and its derivatives will be study. The future direction for photoreforming of biomass and its derivatives were also suggested. Modification of Titania by nanotube structure and doping it with bi-metal consist of transition metal like Ni-Cu opens up opportunities and challenges for other researchers.

Nanoscale morphology and fractal analysis of TiO2 coatings on ITO substrate by electrodeposition.

In this paper, we introduced an advanced discussion of the 3D morphology of TiO2 coatings deposited on ITO substrate by electrodeposition under different deposition times. Atomic force microscopy was applied for obtaining topographic images of the samples. The images were processed using the MountainsMap 8.0 commercial software according to ISO 25178-2:2012. Moreover, fractal theory was applied to study the surface microtexture of coatings. The morphology was affected by the deposition time, where the grain size decreased with the increase of the time, making film's surfaces smoother. In addition, the surface roughness exhibited a random behaviour, but does not presented significant difference between samples. The fractal dimension showed similar values for all coatings. In contrast, surface texture isotropy also exhibited random behaviour. However, advanced fractal parameters revealed that when the deposition time increased, the coatings microtexture has become uniform and less porous. Furthermore, all coatings presented high topographic uniformity, regardless of deposition time. These results revealed that the morphology and microtexture of TiO2 -based coatings can be controlled by the deposition time. LAY DESCRIPTION: An advanced characterization on the micromorphology of 3D morphology, using AFM images, of Titanium dioxide (TiO2 ) coatings deposited on ITO substrate by electrodeposition under different deposition times. TiO2 is one of the most studied semiconductors to make photovoltaic devices. The versatility of this semiconductor is associated with low toxicity, high photochemical stability, abundance, and the facility to obtain by conventional synthesis routes. The obtention of a homogeneous and stable layer in the semiconductor TiO2 film deposition is a crucial stage in the assembly of sensitized photovoltaic devices. Atomic Force Microscopy (AFM) is a technique which can magnify up to a billion times and it uses a tip or probe which touches the sample surface point by point. The tip deflection is interpreted as the surface topography by the software, producing 2D or 3D images that generate several tribological parameters such as roughness in respect to a scanned area, has been a technique widely reported in the morphological characterization, determination of thickness, roughness, and particle size in thin films. Therefore, in this paper, the morphology was studied by atomic force microscopy using MountainsMap commercial software. The main goal was to study the influence of the deposition time on the morphology and microtexture of the material. New parameters such as surface entropy, fractal succolarity and fractal lacunarity were obtained for studying coatings microtexture's complexity.

FABRICATION AND PHOTOCATALYTIC ACTIVITY OF TiO2 NANOTUBES BY HYDROTHERMAL TREATMENT

TiO2 nanotubes were prepared by hydrothermal method using P25 as raw material. The effect of hydrothermal duration and calcination temperature on the crystal structure and morphology of intermediate product and TiO2 was investigated by XRD, SEM and TEM. The photocatalytic activity of TiO2 was evaluated by the degradation of methylene blue. The result revealed the formation process of nanotube and indicated that the photocatalytic activity of TiO2 nanotubes strongly depended on the calcination temperature. The crystallinity of nano-TiO2 was gradually improved with the increasing calcination temperature up to 750 oC resulting in the increase of degradation rate of methylene blue. With further increase in calcination temperature, anatase TiO2 began to transform into rutile phase and the nanotubes completely transformed to particles, leading to the decrease of photocatalytic activity. It was found that TiO2 annealed at 750 oC showed the highest degradation rate, resulting from the excellent crystallinity of anatase phase and nanorod structure.

In English

The use of oxygen modified graphite-like carbon nitride (C3N4Ox), photosensitive in the visible region of the optical spectrum, along with TiO2, photocatalytically active only in the ultraviolet region of the spectrum, in the C3N4Ox/TiO2 binary photocatalyst, opens a possibility of the use of sunlight energy. To increase opportunities of various kinds of photochemistry-related applications of C3N4Ox/TiO2 photocatalyst, the phase composition of the TiO2 matrix and morphology of nanoparticles of composite and their optical properties are very important. A novel composite material, C3N4Ox/TiO2, was synthesized in the present work in accordance with the approach developed in Frantsevich Institute for Problems of Materials Science of NASU for the synthesis of powdered oxygen-doped carbon nitride (C3N4Ox) by CVD method under the special reactionary conditions of the melamine pyrolysis, in particular, in the presence of a fixed air volume. Deposition of C3N4Ox carried out on the surface of a nanostructured powdered TiO2 matrix of different phase composition, rutile or anatase. The deposition of C3N4Ox (~5 % O) on both rutile and anatase nanopowders was confirmed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis-DRS) methods. SEM micrographs (recorded with a MIRA3 TESCAN scanning electron microscope) of nanoparticles of both C3N4Ox/TiO2 composites (anatase and rutile phases) demonstrate the arrangement of TiO2 as separate globular nanoparticles and clusters between the plates and in the channels of the porous scaly plates C3N4Ox. However, the anatase phase nanoparticles (synthesized in IPM NASU) have a higher dispersion, the average size of non-aggregated almost monodisperse particles is about 10 nm. Using UV/Vis spectroscopy, it has been found that a redshift of long-wavelength edge of the fundamental absorption band of the spectra is observed when going from TiO2 (anatase), TiO2 (rutile), C3N4, C3N4Ox/TiO2 (anatase), C3N4Ox/TiO2 (rutile) and, then, to C3N4Ox, and the band gap decreases from 3.2, 3.0, 2.6, 2.4, 2.25 to 2.1 eV in the above sequence of materials. In such a case, C3N4Ox/TiO2 (especially deposited on anatase phase) would absorb more visible light than g-C3N4 and TiO2, by generating more charges which favor the improvement in the photoactivity of the catalysts.

2D square nanosheets of Anatase TiO2: A surfactant free nanofiller for transformer oil nanofluids

Rutile TiO2 nanoparticle with high dielectric constant has already become an automatic choice as a favorable nanofiller for efficacious transformer oil (TO) nanofluids (NFs) development, thanks to their large surface area and splendid electron trapping capacity. In this work, the role of phase and morphology of TiO2 on the properties of TO has been deciphered for the first time. For this, solvothermally prepared ultra-thin, square nanosheets of purely anatase phase TiO2 (a-TiO2) with 50–70 nm dimensions are used for NF preparation in two types of commercial mineral oil. The dielectric breakdown strength and thermo-physical properties of the resultant TO NFs have been investigated thereafter. A significant enhancement (27–30%) in breakdown voltage (BDV) at very low filler fraction (0.005 wt%) due to accelerated charge scavenging capability by virtue of the inherent surface oxygen vacancies, high electronegativity and slightly higher band-gap than rutile phase is observed. Additionally, the thermal conductivity of TO is seen to rise by 13–23% (±5%) at 50C which is facilitated by long phonon lifetime mediated inter-sheet transfer of heat. Further, the electronegativity induced strong repulsive forces among the dispersed nanofillers at ultra-low concentrations leads to a surfactant-free stable liquid insulation over a prolonged time. Besides, the acidity and viscosity, the increment of which with filler fraction causes a serious drawback for NFs, are below par the alarming level of TO due to low filler fraction of a-TiO2. All the above beneficial features along with improved flash and pour points makes the synthesized 2D a-TiO2 a budding candidate for efficient NF development at very low filler fraction without any usage of surfactant.

Titanium dioxide nanotubes with triazine-methacrylate monomer to improve physicochemical and biological properties of adhesives

ObjectiveFormulate experimental adhesives containing titanium dioxide nanotubes (nt-TiO2) or titanium dioxide nanotubes with a triazine-methacrylate monomer (nt-TiO2:TAT) and evaluate the effect of these fillers on the physical, chemical, and biological properties of the adhesives. MethodsFirst, nt-TiO2 were synthesized via a hydrothermal method. The nt-TiO2 were mixed with a triazine-methacrylate monomer (TAT) to formulate nt-TiO2:TAT, which were characterized by transmission electron microscopy (TEM). The nt-TiO2, TAT, and nt-TiO2:TAT were evaluated via Fourier Transform Infrared, Ultraviolet–visible, and micro-Raman spectroscopies. An experimental adhesive resin was formulated with bisphenol A glycerolate dimethacrylates, 2-hydroxyethyl methacrylate, and photoinitiator/co-initiator system. nt-TiO2 or nt-TiO2:TAT were incorporated at 2.5 wt.% and 5 wt.% in the adhesive. The base resin without nt-TiO2 or nt-TiO2:TAT was used as a control group. The adhesives were evaluated for antibacterial activity, cytotoxicity, polymerization kinetics, degree of conversion (DC), Knoop hardness, softening in solvent (ΔKHN%), ultimate tensile strength (UTS), 24 h- and 1 year- microtensile bond strength (μ-TBS). ResultsTEM confirmed the nanotubular morphology of TiO2. FTIR, UV–vis, and micro-Raman analyses showed the characteristic peaks of each material, indicating the impregnation of TAT in the nt-TiO2. Adhesives with nt-TiO2:TAT showed antimicrobial activity against biofilm formation compared to control (p < 0.05), without differences in the viability of planktonic bacteria (p > 0.05). All groups showed high percentages of pulp cell viability. The polymerization kinetics varied among groups, but all presented DC above 50%. The addition of 5 wt.% of nt-TiO2 and both groups containing nt-TiO2:TAT showed higher values ​​of Knoop hardness compared to the control (p < 0.05). The groups with nt-TiO2:TAT presented lower ΔKHN% (p < 0.05) and higher UTS (p < 0.05) than the control group. After one year, the group with 5 wt.% of nt-TiO2, as well as both groups containing nt-TiO2:TAT, showed higher μ-TBS than the control (p < 0.05). SignificanceThe mixing of a triazine-methacrylate monomer with the nt-TiO2 generated a filler that improved the physicochemical properties of the adhesive resins and provided antibacterial activity, which could assist in preventing carious lesions around tooth-resin interfaces. The set of physical, chemical, and biological properties of the formulated polymer, together with the greater stability of the bond strength over time, make nt-TiO2:TAT a promising filler for dental adhesive resins.

Photoelectrochemical performance enhancement of low-energy Ar+ irradiation modified TiO2

To evaluate the effects of surface properties of semiconductor and enhance semiconductor’s activity for photocatalytic water oxidation, low-energy Ar+ irradiation was employed to modify the rutile TiO2 (110) surface and control the formation of oxygen vacancy density in TiO2, which was subsequently used for the photoelectrochemical (PEC) oxygen evolution reaction (OER). Specifically, by controlling the substrate temperature during Ar+ irradiation, the surface morphology and oxygen vacancy density of rutile TiO2 (110) could be modified, such that the effects of surface crystallinity, optical absorption and electrical properties of TiO2 could be compared for OER. We found that the intrinsic activity of TiO2 for PEC OER does not exhibit a scaling relationship with respect to the density of oxygen vacancy, optical adsorption or charge carrier concentration. Rather, a linear relationship could be observed between the photocurrent density and the interfacial charge-transport conductivity. Furthermore, ambient pressure X-ray photoelectron spectroscopy (APXPS) was used to investigate the effect of low-energy Ar+ irradiation on the interaction between TiO2 and water. It was demonstrated that using single crystal model systems with controlled properties, this study has thus provided a clear yet detailed analysis on key factors in tuning the photoelectrochemical performance of TiO2.

Growth of dimensionally favoured TiO2 morphologies by AACVD and their recognized performance as LIB anode

The current effort aims at the morphological displays of TiO2 materials grown on Ti foil substrates using aerosol assisted chemical vapour deposition. Optimization of temperature, surfactant concentrations and substrate orientation has been found to play a vital role in the smart designing of micro/nanostructures, ranging from microspheres, nanopetals, nanospikes to the nanorods. Interestingly, when tested as LIB anode these various morphologies showed a much distinct performance and stability during charge/discharge cycles. The nanorod structures with smooth carbon covering have shown excellent reversibility followed by the nano-petals that showed an impressively stable capacity.

Flexible bacterial cellulose-based BC-SiO2-TiO2-Ag membranes with self-cleaning, photocatalytic, antibacterial and UV-shielding properties as a potential multifunctional material for combating infections and environmental applications

This research study reports the formation of flexible and multifunctional organic-inorganic hybrid membranes (BC-SiO2-TiO2/Ag) based on bacterial cellulose (BC) that contain photoactive (TiO2) and antibacterial (Ag) components, rendering them photocatalytic, self-cleaning and UV-shielding properties (due to TiO2) as well as antibacterial activity. Coating of BC with sol-gel derived silica and titania particles was achieved through hydrolysis-polycondensation of tetraethyl orthosilicate and titanium (IV) isopropoxide, respectively, and a soft hydrothermal treatment (140 °C, 20 h) was used to obtain well-crystalline TiO2. The prepared BC-SiO2-TiO2/Ag photoactive membranes were characterized by an array of analytical techniques including XRD, XRF, SEM-EDS, electronic absorption spectroscopy and vibrational spectroscopy. The morphology of TiO2 coatings changes from a homogenous film-like smooth one to a rougher one consisting of randomly oriented titania particles (170 ± 35 nm) upon increasing the TiO2 loading of the membranes. These prepared photoactive BC-SiO2-TiO2 membranes exhibited excellent TiO2-loading dependent photocatalytic/self-cleaning activity towards crystal violet dye deposited as an over-layer on the surface of the membranes, degrading 97 % of the dye within 50 min of UV illumination. In addition to good photoactivity, the BC-SiO2-TiO2/Ag membranes demonstrated reasonable antibacterial activity against five different bacterial strains under dark conditions. These flexible BC-based hybrid membranes with photocatalytic, self-cleaning, antibacterial properties have the potential to be used in the design of self-cleaning and antibacterial surfaces, filters and facemasks that could be easily disinfected under UV irradiation from a lamp or natural sunlight and safely discarded and even recycled.