TiO2 Nanowires Research Articles

Characterization of Sn@TiO2 Anode Material for Li-Ion Battery Application

In this work, various phases of nanorod TiO2 were fabricated by hydrothermal process. Different crystalline phases of TiO2 nanowires will be analyzed by electrochemical analysis (CV, LSV, C-rate, charge and discharge, and EIS test) to investigate the influence of Li+ diffusion rate on specific capacitance. The in-situ XRD structure for charging and discharging will be carried out to explore the diffusion and structural behavior of Li+ in TiO2 was explored its fast charging, high capacitance and high safety characteristics, which will be a fundamental research of Sn modified on TiO2 nanowire. Transmission electron microscope image showed a range of 20 to 80 nm length TiO2 nanorods was success synthesized, and the XRD indicated the phase were rutile, anatase and rutile/anatase mixed by controlling the chelating agents (citric acid). The specific capacity of TiO2 nanorod was 120 mAh/g which the Columbic efficiency was ~ 99% under 0.1 C. A morphology of Sn@TiO2 was investigated as nano-capsule. The results are supposed to clarify the key factors of the fast charge, high specific capacitance and safety. It is expected that the Li+ ion influence on structure changes during the charge and discharge process by implementing this research. The fast charging, high specific capacity and high safety mechanism will be established as an index for material application and commercial products.Keywords: TiO2 anode materials, Sn@TiO2 anode materials, Li-ion battery, In-operando XRD

High-performance polymer electrolyte membrane modified with isocyanate-grafted Ti3+ doped TiO2 nanowires for lithium batteries

The Ti3+ doped TiO2 nanowires were grafted by tolylene-2,4- diisocyanate (TDI) and applied as a modifier for the preparation of organic–inorganic hybrid electrolyte in high performing lithium batteries. The PEO-based polymer electrolyte was optimized at different organic–inorganic ratios and exhibited excellent lithium-ion conductivity of 1 × 10−4 S·cm−1 at 30 °C when adding 8% TDI-TiO2 nanowires, outstanding electrochemical stability with a wide electrochemical window up to 5.5 V at 60 °C and a high lithium-ion transport number of 0.36. The LiFePO4|PTTNW8%|Li cells deliver excellent rate capability and cycling performance, with a high initial discharge capacity up to 151 mAh·g−1 at 60 °C at 0.1 C rate and excellent capacity retention of 91% after 100th cycle. NCM811|PTTNW8%|Li high-voltage lithium batteries were also demonstrated at a 50 °C, which displayed a superior cycling performance. Therefore, the prepared PEO-TDI-TiO2 electrolyte is a promising polymer electrolyte for solid- state lithium batteries.

Fabrication of energy storage EDLC device based on self-synthesized TiO2 nanowire dispersed polymer nanocomposite films

Fabrication of energy storage EDLC device based on self-synthesized TiO2 nanowire dispersed polymer nanocomposite films

Sieve-Like CNT Film Coupled with TiO2 Nanowire for High-Performance Continuous-Flow Photodegradation of Rhodamine B under Visible Light Irradiation.

Continuous-flow photoreactors hold great promise for the highly efficient photodegradation of pollutants due to their continuity and sustainability. However, how to enable a continuous-flow photoreactor with the combined features of high photodegradation efficiency and durability as well as broad-wavelength light absorption and large-scale processing remains a significant challenge. Herein, we demonstrate a facile and effective strategy to construct a sieve-like carbon nanotube (CNT)/TiO2 nanowire film (SCTF) with superior flexibility (180° bending), high tensile strength (75–82 MPa), good surface wettability, essential light penetration and convenient visible light absorption. Significantly, the unique architecture, featuring abundant, well-ordered and uniform mesopores with ca. 70 µm in diameter, as well as a homogenous distribution of TiO2 nanowires with an average diameter of ca. 500 nm, could act as a “waterway” for efficient solution infiltration through the SCTF, thereby, enabling the photocatalytic degradation of polluted water in a continuous-flow mode. The optimized SCTF-2.5 displayed favorable photocatalytic behavior with 96% degradation of rhodamine B (RhB) within 80 min and a rate constant of 0.0394 min−1. The continuous-flow photodegradation device made using SCTF-2.5 featured exceptional photocatalytic behavior for the continuous degradation of RhB under simulated solar irradiation with a high degradation ratio (99.6%) and long-term stability (99.2% retention after working continuously for 72 h). This work sheds light on new strategies for designing and fabricating high-performance continuous-flow photoreactors toward future uses.

Rutile-phase TiO2@carbon core-shell nanowires and their photoactivation in visible light region

Titanium dioxide (TiO2) has been acknowledged as one of the efficient photocatalysts in the UV region. To extend the photo-absorption region toward visible lights, the TiO2 nanowires enclosed with carbon shells (TiO2@carbon core-shell nanowires) were synthesized by a chemical vapor deposition technique at various temperatures from 650 to 950 °C. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that TiO2 cores and carbon shells are rutile and graphitic structures, respectively. From Raman spectra, the peak intensity of the Eg mode was observed to be redshifted with elevated growth temperatures due to the increase in oxygen vacancies in the TiO2@carbon core-shell nanowires. From X-ray photoelectron spectroscopy (XPS) results, the oxygen vacancies were strongly related to the Ti3+ ions. The UV–visible spectroscopic studies show a possible decrease in photocatalytic energy from 3.1 to 2.7 eV for the TiO2@carbon core-shell nanowires, indicating that the light absorption was enhanced in the visible-light region. The optical absorbance results confirmed the presence of the mid-gap states due to the oxygen vacancies, which are responsible for the visible-light absorption. The photocatalytic activity of the TiO2@carbon core-shell nanowires studied by methylene blue (MB) dye degradation is effective under visible lights.

Effect of dimensionality of nanosized TiO2 embedded in regenerated cellulose beads as a portable catalyst for reusable decomposition system

AbstractFree‐standing titanium dioxide (TiO2) nanowires (TNW) with great photocatalysis performances were formed by using a simple hydrothermal method. Pre‐cool rapid dissolution technique was used to dissolve cellulose, and the regenerated cellulose (RC) beads were used as a portable host for absorption and photocatalytic reaction. Comparisons were made between zero‐dimensional TiO2 nanoparticle (TNP) and one‐dimensional TNW, which both were mixed separately with dissolved cellulose and regenerated into spherical beads. As regeneration involved physical interaction, there were no functional group changes observed on RC beads, as confirmed by Fourier‐transform infrared (FT‐IR) spectroscopy analysis. TNP and TNW maintained the crystallize phase after the regeneration process, thus confirming that aqueous LiOH/urea solvent had no chemical interaction with them. RC beads shaped, external and internal structures were morphologically examined with a field emission scanning electron microscope (FESEM). Due to the distinct dimensionality between TNW and TNP, interactions of physical crosslinking with dissolved cellulose are also different. This leads to different RC beads morphological structures, externally and internally. Changes in pore volume and percentage of weight gain were most prominent with the embedment of TNW. RC beads with TNP (TPB) had better photocatalytic performances than RC beads with TNW (TWB) in the 1st cycle but have poor recyclability in comparison to TWB after the 5th cycle. We concluded that the embedment of one‐dimensional TNW in RC beads promotes better photocatalytic behavior and performance as a portable catalyst.

Laser‐Induced Surface Reconstruction of Nanoporous Au‐Modified TiO2 Nanowires for In Situ Performance Enhancement in Desorption and Ionization Mass Spectrometry

AbstractThe physicochemical properties of nanostructured substrates significantly impact laser desorption/ionization mass spectrometry (LDI‐MS) performance. Fundamental understanding of the substrate properties can provide insights into the design and development of an efficient LDI matrix. Herein, a hybrid matrix of nanoporous Au‐modified TiO2 nanowires (npAu‐TNW) is developed to achieve enhanced LDI‐MS performance. Its origin is investigated based on hybrid matrix properties including photo–thermal conversion and electronic band structure. Notably, further improvement is obtained in the npAu‐TNW than in the pristine TNW and non‐porous Au nanoisland‐modified TNW (Au‐TNW) hybrid, which is attributed to the laser‐induced surface restructuring/melting phenomenon. Noticeable surface restructuring/melting occurs in the npAu by laser exposure through efficient photo–thermal conversion of the highly porous npAu. At this instant of npAu structural changes, internal energy transfer from the npAu to the adsorbed analyte is promoted, which facilitates desorption. Moreover, strain is developed in situ in the TNW adjacent to the restructuring npAu, which distorts the TNW lattice. The strain development reduces recombination rates of charge carriers by introducing shallow trap levels in the bandgap, which enhances the ionization process. Ultimately, the high LDI‐MS performance based on the npAu‐TNW hybrid matrix is demonstrated by analyzing neurotransmitter.

TiO2 Nanowire Arrays in situ Grown on Ti Foil Exhibiting Superior Uranyl-Adsorption Properties

TiO2 nanowire arrays in situ grown on Ti foil (TiO2/Ti) were prepared to remove uranium (VI) from aqueous solution. As the Ti foil serves as a carrier for TiO2, the TiO2/Ti adsorbent can be effortlessly retrieved from aqueous solutions by tweezers after adsorption. The presence of TiO2 nanowire arrays on Ti foil was verified by X-ray diffraction and scanning electron microscopy. Parameters in the adsorption process were fully evaluated, including solution pH, contact time, temperature, and uranium (VI) concentration. The adsorption was most efficient in the pH range of 5.0 to 9.0. The maximum uranium (VI) adsorption capacity of TiO2/Ti, based on the Langmuir model, was 354.5 mg g–1 at pH 5.0 and T = 323 K. Thermodynamic parameters showed that the adsorption of uranium (VI) on TiO2/Ti is endothermic and spontaneous. The adsorption capacity of TiO2/Ti remained essentially unchanged after three adsorption–desorption cycles in uranium (VI) solutions. Our results support the application of this adsorbent to removal of uranium (VI) from diversified aqueous samples.

Branching TiO2 nanowire arrays for enhanced ethanol sensing

Nanostructure modulation is effective to achieve high performance TiO2-based gas sensors. We herein report a wet-chemistry route to precipitate directly branched TiO2 nanowire arrays on alumina tubes for gas sensing applications. The optimized branched TiO2 nanowire array exhibits a response of 9.2 towards 100 ppm ethanol; whilst those of the pristine TiO2 nanowire array and the branched TiO2 nanowire powders randomly distributed are 5.1 and 3.1, respectively. The enhanced response is mainly contributed to the unique porous architecture and quasi-aligned nanostructure, which provide more active sites and also favor gas migration. Phase junctions between the backbone and the branch of the branched TiO2 nanowire arrays help the resistance modulation as a result of potential barriers. The facile precipitation of quasi-aligned arrays of branched TiO2 nanowires, which are in situ grown on ceramic tubes, thus provides a new economical synthetic route to TiO2-based sensors with excellent properties.

Synthesis of hierarchical and flower-like TiO2 nanowire microspheres as biocompatible cell carriers

Fibrous materials are of great interest in the development of tissue regenerative matrix. However, synthesis of inorganic fibrous microspheres as cell carriers is a great challenge. In this study, we for the first time report on the synthesis of novel hierarchical and flower-like TiO2 nanowire (NW) microspheres as biocompatible cell carriers. TiO2 NW microspheres were synthesized through in situ alkali hydrothermal treatment of the TiO2 nanoparticle (NP) microspheres and their microstructure, formation mechanism and in vitro biocompatibility were evaluated. SEM observations show that the resulting TiO2 NW microspheres were constructed by a large number of NWs with the diameter of 10–20 nm and exhibited a flower-like and hierarchical morphology with the diameter of 400–600 μm. XRD patterns indicate that TiO2 NW microspheres were constructed by both rutile and anatase phase of TiO2. FT-IR spectra reveal that Ti-O-Ti bonds were involved in TiO2 NW microspheres. In vitro biocompatibility was evaluated by seeding the fibroblast L929 cells on the microspheres. A conventional MTT assay quantitatively indicates that the TiO2 NW microspheres favored adhesion and proliferation of cells and were biocompatible, while SEM observations qualitatively confirmed that the cells were well grown on the surface of TiO2 NW microspheres. Thus, the as-synthesized TiO2 NW microspheres would be applicable to novel and biocompatible cell carriers.

Microplasma synthesis of titanium dioxide nanowires

In this work we developed a process to produce titanium dioxide nanowires through microplasma synthesis in atmospheric conditions. The titanium dioxide nanowires grow on the surface of the titanium anode. During initial synthesis, free chlorine anions form and migrate to the Ti anode creating various Ti-Cl complexes (TiCl4). H2O2 molecules are decomposed at the titanium anode to form OH species that react with the Ti-Cl complexes forming TiO2 nanowires. The microplasma environment is ideal for creating titanium dioxide nanowires through the creation of several reactive species that typically require reaching high temperatures (>300 °C). The anode and cathode materials were varied along with the liquid electrode composition for determining the reaction mechanisms involved and analyzed through EDS and XRD techniques.

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.

Solid-State Solar Cells Based on TiO2 Nanowires and CH3NH3PbI3 Perovskite

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage Voc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (Vbi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.

Boosting the electrochromic performance of TiO2 nanowire film via successively evolving surface structure

Boosting the electrochromic performance of TiO2 nanowire film via successively evolving surface structure

Multiple Applications of CdS/TiO2 Nanocomposites Synthesized via Microwave-Assisted Sol–Gel

A novel multi-functional CdS/TiO2 nanocomposite was synthesized by using a wet impregnation method and microwave-assisted sol–gel anatase TiO2. A hydrothermal approach was used to prepare TiO2 nanowire then decorated with CdS-NPs. XRD, FTIR, HRTEM, FE-SEM, EDX, XPS, and optical properties were exploited to investigate their characteristics. A 0.05 M CdS/TiO2 showed high degradation efficiency toward methylene blue dye using UV–Vis light. The degradations were 95.46, 88.94, and 54.86% for CdS/TiO2, TiO2-NWs, and CdS-NPs, respectively. Different parameters that affect the degradation process were studied. Antibacterial activity of nanocomposites was carried out against pathogenic bacteria using diffusion methods. The hybrid nanocomposite CdS/TiO2 also showed larvicidal activity against Culex pipiens.

Anatase TiO2 nanowires intertangled with CNT for conductive additive-free lithium-ion battery anodes

Although the typical anatase TiO2/C nanocomposite electrodes have improved rate properties and capacities compared to pure anatase TiO2 counterparts, their excess inactive carbon components, such as C and conductive additive (acetylene black), will be bad for the gravimetric energy densities and initial coulombic efficiencies of batteries. Obtaining improved gravimetric energy densities and initial coulombic efficiencies is vital to the development of TiO2-based lithium-ion battery anodes, but there are challenges. Herein, a novel TiO2-based composite (TiO2@CNT) consisting of anatase TiO2 nanowires intertangled with CNT (3 wt%) has been fabricated and assessed as a conductive additive-free anode for lithium-ion batteries. Results demonstrate that thus TiO2@CNT shows impressive electrochemical properties, revealing 96% initial coulombic efficiency, 161 mA h g−1 at 1C after 260 cycles and 108 mA h g−1 at 10C after even 1400 cycles. Compared with the typical TiO2/C composite electrodes, thus TiO2@CNT electrode without conductive additive exhibits higher initial coulombic efficiency and will have an advantage in gravimetric energy density due to low content of inactive carbon. Therefore, this work could provide an insight into improvement of electrochemical properties of the TiO2-based anodes in terms of specific capacity, initial coulombic efficiency and gravimetric energy density.

Fabrication of rutile – TiO2 nanowire on shape memory alloy: A potential material for energy storage application

Herein, we reported a novel and a facile method to fabricated TiO2 nanowire arrays on Nitinol alloy substrate as electrode material for supercapacitors. The rutile TiO2 nanowire arrays on alloy substrates were developed using chemical vapor deposition technique with camphor as the source. A systematic study for the growth of nanostructure TiO2@NiTi has been carried out along with its exceptional physical and chemical properties for energy storage application. The growth of the nanostructure for different concentration at the elevated temperature has been studied through different characterization techniques like scanning electron microscopy, X-ray diffraction and Raman spectroscopy, which resulted in confirming the formation of rutile phase having length and diameter of 10 ± 3 µm and 80 ± 10 nm, respectively. In addition, the COMSOL simulation was carried out to determine the temperature gradient in the furnace tube at elevated temperature. The presence of nickel in the bi-metallic alloys played a vital role in the growth of TiO2 nanostructures array. The synthesized TiO2 nanowire arrays on Nitinol substrate exhibited the specific capacitance of ∼ 1F/g with long term stability, making it a potential candidate for supercapacitor applications.

Graphene oxide charge blocking layer with high K TiO2 nanowire for improved capacitive memory

Glancing angle deposition technique was adopted to fabricate TiO2 nanowire (NW) over spin coated graphene oxide (GO) thin-film (TF) for capacitive memory application. The formation of hybrid structure was studied using field emission scanning electron microscope. High accumulation capacitance of 0.994 nF/cm2 at 7 MHz frequency was obtained for fabricated Au/TiO2 NW/GO TF/Si device as compared to Au/TiO2 NW/Si device (0.4014 nF/cm2). A theoretical study using delta depletion model was done, which further validated the relative permeability and flat band voltage of the devices at higher frequency. The memory window of Au/TiO2 NW/Si was found to be 1.36 V at±10 V, which increased to 3.72 V for Au/TiO2 NW/GO TF/Si hybrid device. Also, a large charge storage capacity with good retention (105 s) and endurance (1000 cycles) was observed for the hybrid device. Moreover, Au/TiO2 NW/GO TF/Si device exhibited low leakage current density of 1.6 µA/cm2 at +1 V as compared to Au/TiO2 NW/Si device (11.3 µA/cm2 at +1 V). The GO TF layer at the bottom increased the potential difference between TiO2 and GO, which acted as a charge trapping layer and thus demonstrated as a good candidate for non-volatile memory application.

Preparation of a novel TiO2-graphene 3D framework material for efficient adsorption-photocatalytic removal of micro-organic contaminants from water

Micro-organic contaminants (MCs) have become potential source of aqueous environmental micro-pollution and TiO2 based 3D framework materials show great superiority for effectively overcoming the mass transfer resistance of MCs. Herein, a novel TiO2-graphene 3D framework material (3D TiO2/rGO) was prepared by rapid freezing-drying followed by high temperature hydrogen reduction, in which TiO2 nanowires (TiO2 NWs) and graphene oxide (GO) nanosheets were used as precursors and no organic components and templates were added. The as-prepared 3D TiO2/rGO exhibited significantly enhanced adsorption-photocatalytic activity for low concentration ethenzamide, one of the representative MCs in water. When the adsorbent dosage was 7.5 mg/150 mL, the removal rate of 500 ppb ethenzamide attained 98.5% in 60 min and the photocatalytic rate was 2.2 times of pristine TiO2 NWs and 17.4 times that of TiO2/GO under UV light irradiation, respectively and 99.8% ethenzamide was eliminated in 3 min and the photocatalytic rate was 1.89 times that of pristine TiO2 NWs and 2.83 times that of TiO2/GO under VUV light irradiation, respectively. The joint action of h+, •OH, •O2− and oxygen vacancies contributed to the photocatalytic removal of MCs and the as-prepared TiO2 based 3D framework material shows great potential for highly efficient removal of MCs from water.

Enhanced Photoelectrochemical Reaction of MoS2 Nanosheets Vertically Grown on TiO2 Nanowires

We report the growth and enhanced photoelectrochemcial (PEC) water-splitting reactivity of few-layer MoS2 nanosheets on TiO2 nanowires. TiO2 nanowires with lengths of ~1.5 ~ 2.0 μm and widths of ~50~300 nm are synthesized on fluorine-doped tin oxide substrates at 180 oC using hydrothermal methods with Ti(C4H9O)4. Few-layer MoS2 nanosheets with heights of ~250 ~ 300 nm are vertically grown on TiO2 nanowires at a moderate growth temperature of 300 oC using metalorganic chemical vapor deposition. The MoS2 nanosheets on TiO2 nanowires exhibit typical Raman and ultraviolet-visible light absorption spectra corresponding to few-layer thick MoS2. The PEC performance of the MoS2 nanosheet/TiO2 nanowire heterostructure is superior to that of bare TiO2 nanowires. MoS2/TiO2 heterostructure shows three times higher photocurrent than that of bare TiO2 nanowires at 0.6 V. The enhanced PEC photocurrent is attributed to improved light absorption of MoS2 nanosheets and efficient charge separation through the heterojunction. The photoelectrode of the MoS2/TiO2 heterostructure is stably sustained during on-off switching PEC cycle.