Ti Nanorods Research Articles

Effect of various metallic nanoparticles on plasmon-enhanced solar absorption efficiency.

Solar thermal conversion technology has attracted significant attention because it ensures sustainable and modern clean energy generation. The usage of plasmonic nanofluids as the working media is a useful strategy to collect solar energy. In this study, the optical properties of various individual nanospheres (NPs) and nanorods (NRs)--Au, Ag, Cu, Fe, Mg, Mn, Mo, Pb, Ti, Li, and Al--and their effect on the solar absorption efficiency factor (SAEF) with a solar wavelength between 300nm and 1100nm are determined using COMSOL Multiphysics software. For NPs, the SAEF is divided into three parts. In the first part with a radius lower than 35nm, an Li NP has the highest SAEF of 1.3992. In the second part, with a radius between 35nm and 50nm, the Au and Cu NPs have the highest SAEFs of 1.1963 and 1.2469, respectively. In the third part, with a radius between 50nm and 90nm, the maximum SAEFs of Fe (1.5682 at radius of 75nm), Pt (1.4914 at radius of 90nm), Ti (1.4348 at radius of 75nm), and Mn (1.4614 at radius of 75nm) can be obtained. Compared to NPs, the SAEF of an NR greatly depends on the aspect ratio (AR) and the effective radius (r e f f ). We observe that the SAEFs of Ag, Al, Au, Cu, Fe Mg, Mn, Mo, and Ti NRs are much stronger than that of corresponding NPs with the same r e f f . The results obtained from the present study provide fundamental information and guidelines to choose optimal NPs for enhancements in solar energy harvesting.

Design of high SERS sensitive substrates based on branched Ti nanorods

This paper reports a rational design of branched titanium (Ti) nanorods formed by glancing angle physical vapor deposition and their applications as substrates for surface-enhanced Raman scattering (SERS). Ti nanorods with branches have larger surface areas than non-branched nanorods. However, Ti surface oxidizes easily resulting in very little SERS effect. The SERS sensitivity of the branched titanium nanorod is improved by annealing Ti nanorods in nitrogen in an effort to reduce oxidation. Additionally, the plasmonic resonance of the branched titanium nanorod is further improved by coating the top of the nanorods and branches with silver (Ag). The sensitivity of the SERS substrates is about 3700% that of as-deposited branched Ti nanorods with a native oxide layer. Our investigation provides a mechanism to fabricate sensitive SERS sensors of Ti nanorods that are known to be thermally and chemically stable and compatible with silicon-based electronics.

Branching of Titanium Nanorods.

One dimensional titanium nanorod structures formed by glancing angle physical vapor deposition have branches while other hexagonal closed packed metals do not. Based on physical vapor deposition and characterizations using electron microscopy and X-ray diffraction, this paper reports that Ti nanorod branching occurs at a low homologous temperature of 0.28. The side surface of the nanorods consists of {} facets arranged in a zigzag shape. Further, branches form on the {} side facets that are parallel to the deposition flux. The length of the branches increases as they are farther away from the nanorod top and tend to reach a constant. The top surface facet of Ti nanorods is {0001} and that of the branches is {}. The insight into conditions for branching, together with the determination of the morphology and crystal orientation of the branches, lay the foundation for further studies of branching mechanisms and driving force.

Metallic and porous Ti nanorod arrays for visible-IR light absorption and dendrite-free stable lithium-metal batteries

It is still a challenging task to prepare highly porous nanorod arrays of metals formed on substrates for optical and energy storage applications. Herein, we demonstrate the design and synthesis of black color, metallic and highly porous Ti nanorod arrays as novel current collectors for dendrite-free and highly stable Li-metal anodes. The high porosity of metallic nanorod arrays provides numerous heterogeneous nucleation sites and huge contact area and large space for the accommodation of Li metal. The conductive metallic Ti nanorod arrays enhance electrode integration. Effectively, it eliminates formation Li dendrites and demonstrates superior cycling stability over 300 cycles. Additionally, the unique porous structures of the nanorod arrays can decrease the amplitude of forced vibration in narrow space leading to light absorption. Interestingly, the metal is black instead of metallic color. The black metallic nanorod arrays can absorb more than 96% of both visible and infra-red lights. This black color metallic porous nanorod arrays may find additional applications in aerospace, energy, biomedical, defence, and chemical industries.

C-Dot TiO2 nanorod composite for enhanced quantum efficiency under direct sunlight.

C-Dots obtained from a sustainable route (melon-rinds were used as the source) were combined with TiNRs to create a composite via a simple hydrothermal technique. The obtained materials were subjected to analyses viz. FESEM, XRD, Raman spectroscopy, XPS, PL, FTIR and UV-vis-DRS for understanding their intrinsic nature. The solar photocatalytic performance was evaluated by the degradation of methyl orange (MO) as a model pollutant. The optical properties indicated that there was a clear redshift in the composite with a band gap of 2.49 eV, while the XRD results corresponded to a calculated crystalline size of 24.80 nm. The PL analysis proved the role of C-dots as an electron surge to the TiNRs. The photocatalytic reaction was faster with C-dots as compared to the solo TiNR with a higher degradation of 93.3% within 150 min obeying pseudo-first order kinetics with a rate constant k = 0.01723 min−1. The charge carrier scavenging investigation showed the role of numerous reactive oxygen species (ROS) on the degradation of MO. The formulated composite has demonstrated its ability in effectively handling the contaminants in water. Thus, this study establishes the two-step thermal method as an easy, facile, environmentally-friendly, and low-cost synthesis method for the large-scale production of a photocatalyst.

Hierarchically structured photoanode with enhanced charge collection and light harvesting abilities for fiber-shaped dye-sensitized solar cells

The performances of fiber dye-sensitized solar cells (FDSSCs), in terms of charge collection efficiency, light-harvesting ability, and structural stability, are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire substrate. The microridge made of several Ti micropits is inserted into TiO2 layer to shorten the photoelectron transport distance from the original place in the TiO2 layer to substrate and to increase the electron transport rate. The Ti micropits are used as light-gathering centers to collect the reflected light. Meanwhile, the Ti nanorods are evenly distributed on the surface of the microridge-coated Ti wire substrate, which increases the contact area between the substrate and the TiO2 layer in order to suppress the electron recombination and scatters the incident light to further improve the light-harvesting ability. Therefore, the charge collection and power conversion efficiencies of the novel FDSSC have been accordingly enhanced by 17.7% and 61.6%, respectively, compared with traditional FDSSC. Moreover, the structural stability of the novel FDSSC has been strengthened.

T-Nb2O5 quantum dots prepared by electrodeposition for fast Li ion intercalation/deintercalation

T-Nb2O5 quantum dots were electrodeposited on Ti nanorod arrays to prepare Ti@T-Nb2O5 core–shell array electrodes. The particle size of T-Nb2O5 could be manipulated by adjusting the depositing current density, and quantum dots several nanometers in size could be obtained at a deposition current of 6 mA cm–2. Benefiting from the ultra-small particle size of T-Nb2O5 and the array structure, Ti@T-Nb2O5 nanorod arrays exhibited good rate capability and durability when used as self-supported Li ion battery anodes. The arrays possessed capacities of 350 and 70 mAh g–1 at rate currents of 0.06 and 30 A g–1, respectively. Furthermore, the electrodes maintained 500 cycles without obvious decay at a high rate current of 30 A g–1.

Bioadaptive Nanorod Topography of Titanium Surface to Control Cell Behaviors and Osteogenic Differentiation of Preosteoblast Cells

Titanium (Ti) nanorods fabricated using selective corrosion of Ti substrate by anodic technology show better biocompatibility with pre-osteoblast cells. The current study investigated the response of the murine pre-osteoblast cell MC3T3-E1 on Ti nanorod topography and untreated Ti surfaces by means of examination of the morphology and osteogenic differentiation responsible for the pre-osteoblast reaction. The morphology of MC3T3-E1 cells was observed using scanning electron microscopy, and alkaline phosphatase (ALP) activity was measured using a colorimetric assay after incubation for 7, 14, and 21 days. The expression of three osteogenic differentiation markers including ALP, osteocalcin (OCN), and collagen type 1A1 (COL1A1) and two transcription factors including runt related transcription factor 2 (Runx2) and osterix (Osx) at different time points was detected using real-time polymerase chain reaction analysis in both groups. Osx was used to confirm the protein level. The results showed that Ti nanorod surfaces provided prolonged higher levels of ALP activity compared with unmodified Ti surface on the 14th and 21st days. Gene expression analysis of ALP, OCN, and COL1A1 showed significant upregulation with modified nanorod topography after incubation for 14 and 21 days. Osteogenic transcription factors of Runx2 and Osx exhibited changes consistent with the osteogenic differentiation markers, and this may contribute to the persistently active differentiation of MC3T3-E1 cells in the Ti nanorod group. These results demonstrated that the current nanostructured surface may be considered bioadaptive topography to control cellular behaviors and osteoblast differentiation. The in vivo performance and applicability are further required to investigate osseointegration between implant and host bone in the early stages for prevention of aseptic implant loosening.

Ti nanorod arrays with a medium density significantly promote osteogenesis and osteointegration.

Ti implants are good candidates in bone repair. However, how to promote bone formation on their surface and their consequent perfect integration with the surrounding tissue is still a challenge. To overcome such challenge, we propose to form Ti nanorods on their surface to promote the new bone formation around the implants. Here Ti nanorod arrays (TNrs) with different densities were produced on pure Ti surfaces using an anodizing method. The influence of TNr density on the protein adsorption as well as on the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 pre-osteoblastic cells were assessed. The TNrs were also implanted into the bone defects in rabbits to test their application in promoting bone formation and osteointegration at the implant-bone interface. TNrs with the medium density were found to show the best capability in promoting the protein adsorption from surrounding medium, which in turn efficiently enhanced osteogenic differentiation in vitro and osteointegration in vivo. Our work suggests that growing TNrs with a medium density on the surface of traditional Ti implants is an efficient and facile method for promoting bone formation and osteointegration in bone repair.

Effects of Different Lengths of Ti Nanorods Topography on Mesenchymal Stem Cell Growth and Proliferation.

Total hip and knee arthroplasty have being successfully performed in world-wide in recent years. However, poor osseointegration between implant (polish surface) and host bone tissue is one of the main causes for aseptic loosening in Ti-based materials and result in failure. Fabricating nanotopography is a promising method to improve cell behaviors and promote osseointegration. Ti nanorods array of vary lengths have been produced via selective corrosion of Ti substrate using electrochemical anodization technique on titanium surface. In this study, we investigated the murine bone mesenchymal stem cell (MSC) behaviors in response to these different lengths of nanorods. The result showed that the nanorod of 100 nm length increased MSCs adhesion and proliferation. Increased elongation of cytoskeleton actin was also observed on 100 nm height, which resulted in substantially up-regulation of alkaline phosphatase (ALP) activity, suggesting greater bone-forming ability than control Ti. The Ti nanorods of 100 nm length may be a promising implant surface to improve the osseointegration.

Ubiquitous element approach to plasmonic enhanced photocatalytic water splitting: the case of Ti@TiO2 core-shell nanostructure

We demonstrate a new approach to plasmonic enhanced photocatalytic water splitting by developing a novel core-shell Ti@TiO2 brush nanostructure where an elongated Ti nanorod forms a plasmonic core that concentrates light inside of a nanotubular anodic TiO2 shell. Following the ubiquitous element approach aimed at providing an enhanced device functionality without the usage of noble or rare earth elements, we utilized only inexpensive Ti to create a complex Ti@TiO2 nanostructure with an enhanced UV and Vis photocatalytic activity that emerges from the interplay between the surface plasmon resonance in the Ti core, Vis light absorption in the Ti-rich oxide layer at the Ti/TiO2 interface and UV light absorption in the nanotubular TiO2 shell.

The Ti@MoOx nanorod array as a three dimensional film electrode for micro-supercapacitors

Ti@MoOx core–shell nanorod arrays with diameters within 100nm were fabricated by electrodepositing MoOx on a Ti nanorod array prepared by oblique angle deposition. A high areal capacitance of 27mFcm−2 and satisfactory cycling stability were obtained. After post-annealing, MoO2 grains were introduced to enhance the rate capability, suggesting a potential pseudocapacitive micro-electrode.

Ti nanorod arrays with periodic density fabricated via anodic technology

Fabrication of the anodic metals nanorod, especially Ti (titanium) nanorod arrays (Ti-NRAs), has attracted increasing attention in recent years. In this reported work, Ti-NRAs were prepared by applying a constant current of 200 mA under different anodisation conditions. The field emission scanning electron microscopy results showed that the density of the Ti-NRAs could be periodically tuned by the conditions of electrochemical anodisation. A possible formation mechanism is proposed to demonstrate the periodical tuning of the Ti-NRAs' density by the electrochemical anodisation time. This well-controlled synthesis approach may shed light on the fabrication of similar nanostructures of other metal materials.

Vertical Ti doped ZnO nanorods based on ethanol gas sensor prepared on glass by furnace system with hotwire assistance

High density vertical Ti doped ZnO (ZnO:Ti) nanorods (NRs) were uniformly grown on ZnO/glass substrate at 600°C by a furnace system with Ti hotwire assistance. The Ti dopant concentrations are 0.87% and 1.86at.%. The XRD and HRTEM images of ZnO:Ti NRs revealed a wurtzite structure oriented in the c-axis direction. The XRD (002) peaks of the 0.87% and 1.86% Ti-containing samples are shifted to a smaller angle by approximately 0.04° and 0.23°, respectively. That photoluminescence (PL) dominated indicates that the increasing Ti dopant has a great amount of oxygen vacancies by observed green band increasing. The UV band of the PL spectra was blue shifted and increased with increasing Ti. The TEM–EDX mapping images reveal that the majority of Ti atoms are located at the top of the ZnO:Ti NRs. The conductivity of 1.86% Ti-containing samples was 80.7 times higher than the pure ZnO NRs. The ethanol gas responses of the ZnO:Ti NR sensor were around 27.5%, 66.7%, 117.1%, 183.5%, 276.5% and 389.5% when the ethanol gas concentration was 10, 50, 100, 250, 500 and 1000ppm, respectively. The ethanol gas responses of the ZnO:Ti NRs are higher than that of the ZnO NRs by around 5.1 times at ethanol 1000ppm concentration.

Anodic formation of Ti nanorods with periodic length

In this paper, one-dimensional homogeneous Ti nanorods are fabricated via selective corrosion of Ti substrate using electrochemical anodization technique. The nanorod length can be tuned periodically by tailoring the electrochemical conditions. A possible mechanism is proposed to explain the formation of Ti nanorods with periodic length.

Photocatalytic Properties of TiO2 Nanostructures Fabricated by Means of Glancing Angle Deposition and Anodization

Structural, optical, and photocatalytic properties of various nanostructures prepared by glancing angle deposition (GLAD) and by electrochemical anodic oxidation of Ti have been studied. The nanorods were prepared on unheated glass substrates by using reactive sputtering of Ti in the GLAD regime. nanotubes and brush-type nanostructures were fabricated by anodic oxidation of flat Ti films and Ti nanorods prepared by GLAD, respectively. The optical studies revealed that the nanotubes and brush-type nanostructures possess antireflection properties. The photocatalytic activity of nanostructures was characterized by following decomposition of isopropanol under visible and UV light irradiation and found to be significantly higher in nanostructured samples than in their flat counterparts. Also, nanotubes and brush-type nanostructures showed superior photocatalytic activity in comparison with nanorods due to a significantly higher specific surface area.

Hierarchically Organized Micro/Nano-Structures of TiO2

We have developed a technique for the fabrication of hierarchically organized micro/nano-structures of TiO2 by means of anodic oxidation of Ti nanorods prepared by glancing angle deposition. The fabricated nanostructures consist of small TiO2 nanotubes that form brush-type shells around long central oxide cores. This multiscale organization of the nanostructures satisfies requirements for large and accessible surface area while providing direct path for electrons, which are desirable for photocatalytic applications.

Hydrogen storage and cycling properties of a vanadium decorated Mg nanoblade array on aTi coated Si substrate

A 2.25 at.% V decorated Mg nanoblade array has been fabricated by a dynamic shadowinggrowth technique. It can absorb and desorb hydrogen rapidly at temperaturesT>500 Kafter activation by one hydrogenation cycling, with low hydrogen absorption activation energy of35.0 ± 1.2 kJ/mol H2 and desorptionactivation energy of 65.0 ± 0.3 kJ/mol H2. The saturated hydrogen content in Mg nanoblades decreases gradually withthe number of cyclings, which is mainly caused by the formation and growth ofMg2Si hillock defects at the nanoblade/substrate interface even though a diffusion barrierlayer consisting of a 500 nm Ti nanorod array and 500 nm Ti film was depositedbetween the Mg nanoblades and the Si substrate. The improved hydrogen sorptionkinetics is attributed to both the catalytic effect of the V coating and the uniquenanoblade morphology with large surface area and small hydrogen diffusion length.

The role of Mg 2Si formation in the hydrogenation of Mg film and Mg nanoblade array on Si substrates

In this paper, both an Mg film and an Mg nanoblade array have been first fabricated directly on Si substrates and hydrogenated under 20 bar hydrogen pressure at temperatures ranging from 200 °C to 350 °C. It is found that Mg 2Si alloy starts to form at T = 200 °C in both the Mg samples, which produces a two-layered structure in the hydrogenated films with the bottom dense layer of Mg 2Si. To prevent Mg alloying with Si, a layer of 200 nm thick Ti film was deposited in between the Mg samples and Si substrates as a diffusion barrier, and their hydrogenation results show that Mg 2Si formation is suppressed greatly and even eliminated in nanoblades, though Mg 2Si hillock defects are observed in the hydrogenated films, which could be formed progressively through the pinholes in the Ti film. To improve the diffusion barrier, a unique structure, consisting of layers of Ti nanorod array and Ti film, has been designed for Mg-based nanostructure deposition. The hydrogen cycling study demonstrates that the structure of 450 nm Ti nanorods on 1 μm Ti film can endure enough number of cycles for the hydrogen storage kinetic and thermodynamic study of film-based Mg nanostructures with/without nanocatalyst, and thus one can gain a fundamental understanding of hydrogen interacting with Mg intrinsic nanostructures and nanocatalysts.

Anodic Oxidation of Titanium Nanorods

Anodic oxidation of Ti nanorods prepared by glancing angle deposition has been used for the fabrication of brush-type nanostructures of TiO2. During the anodization process, small TiO2 nanotubes grew on the walls of Ti nanorods until all Ti was converted to the oxide. As a result we obtained highly porous material that consists of TiO2 nanotubes arranged in shells around central oxide cores, which replaced former Ti nanorods. The combination of glancing angle deposition and anodization techniques creates unique possibilities for the fabrication of TiO2 nanostructures with a hierarchical ordering.