TiO2 Nanofilms Research Articles

Amorphous TiO2 nanofilm interface coating on mesoporous carbon as efficient sulfur host for Lithium–Sulfur batteries

Lithium sulfur (Li–S) batteries are regarded as one of the most promising next-generation secondary batteries. However, the insulating nature of active materials, inevitable shuttle effect caused by dissolution of intermediate polysulfides, and severe volume expansion during lithiation prevent their practical application. Herein, we report a novel sulfur host composed of amorphous TiO2 nanofilm interfaces coating on mesoporous carbon by controlling the hydrolytic process of tetrabutyl titanate on the surface of 3D interconnect conductive carbon matrix. The sulfur host shows high surface area, considerable electrolyte wetting capability and strong absorption for lithium polysulfides. Owe to the rational design and outstanding properties, the sulfur cathode with the high active material content of ∼74% and mass loading of ∼3.2 mg cm−2 exhibits a high initial specific capacity of 1455 mAh·g−1 and maintained 1242 mAh·g−1 after 200 cycles at 0.1 C (1C = 1675 mAh·g−1) current density, and also delivers excellent long term cycling performance at 1 C with initial capacity of 720 mAh·g−1 and capacity remained up to 81% after 1000 cycles.

TiO2 Nanofilms on Polymeric Substrates for the Photocatalytic Degradation of Methylene Blue

A low-temperature process to synthesize and print photoactive TiO2 nanofilms onto polymeric substrates using a modified desktop inkjet printer is presented. The coated substrates were assembled in ...

Development of alcohol sensor using TiO2-Hydroxyapatite nano-composites

This work demonstrates successful utilization of thick films of hydroxyapatite (HAp), nano titanium dioxide (TiO2) and its composite coated on glass substrate using screen printing method for alcohol sensing application. Films of various compositions nano TiO2 in HAp were prepared via physical mixing 0.5, 1, 1.5 and 2 wt% of nano TiO2 in HAp. Gas sensing measurement of 1 wt% TiO2-HAp shows efficient sensing at operating temperatures of 33, 35 and 55 °C for methanol, ethanol and propanol gases, respectively, as compared with pure HAp, nano-TiO2 and other composite films. Fast response and recovery time were observed in 1 wt% TiO2-HAp for 10 ppm methanol (50 and 20 s), ethanol (170 and 20 s) and propanol (100 and 70 s), respectively, as compared with pure HAp, nano TiO2 and other composites. It is concluded that nano TiO2 and HAp composite film sensors can be efficiently used to detect alcohol vapors with their presence in ambient as low as 10 ppm concentration.

Influence of nanoscale TiO2 film thickness on gas sensing properties of capacitor-like Pt/TiO2/Pt sensing structure

Due to the combustible and explosive nature of hydrogen, it is important to keep its safety during the production, storage, transportation and utilization. To this context, new type of sensors based on TiO2 nano-films with 100, 50 and 30 nm thickness and capacitor-like sandwiched Pt/TiO2/Pt structure were fabricated to monitor the hydrogen leakage. The gas sensing tests indicate that sensing performance improved with the decrease of TiO2 film thickness thus the sensors with 30 nm thick TiO2 film show higher performance in terms of response (6.16 × 104 to 1000 ppm H2) and response time (25.2 s). Moreover, tests also prove that humidity shows a negative effect on the performance. To investigate the sensing mechanism, temperature dependent resistance (R-T) and voltage dependent current (I-V) measurements was performed. The structure and surface topography of the TiO2 film is characterized by the GIXRD and AFM, respectively. In addition, the elemental depth profile of the sensor was studied by the XPS, about 0.9 at.% Pt element was clearly observed in the middle region of the annealed TiO2 layer. Based on the hydrogen diffusion, sensing mechanism of the presented structures is discussed.

A bioinspired optoelectronically engineered artificial neurorobotics device with sensorimotor functionalities

Development of the next generation of bio- and nano-electronics is inseparably connected to the innovative concept of emulation and reproduction of biological sensorimotor systems and artificial neurobotics. Here, we report for the first time principally new artificial bioinspired optoelectronic sensorimotor system for the controlable immitation of opto-genetically engineered neurons in the biological motor system. The device is based on inorganic optical synapse (In-doped TiO2 nanofilm) assembled into a liquid metal (galinstan) actuator. The optoelectronic synapse generates polarised excitatory and inhibitory postsynaptic potentials to trigger the liquid metal droplet to vibrate and then mimic the expansion and contraction of biological fibre muscle. The low-energy consumption and precise modulation of electrical and mechanical outputs are the distinguished characteristics of fabricated sensorimotor system. This work is the underlying significant step towards the development of next generation of low-energy the internet of things for bioinspired neurorobotic and bioelectronic system.

Carbon quantum dots bridged TiO2 and Cd0.5Zn0.5S film as solid-state Z-scheme photocatalyst with enhanced H2 evolution activity

Abstract Traditional type II heterojunction photocatalyst usually has excellent activities due to the improved charge transfer between the matched band structures of each component, but this is also accompanied by reducing the oxidation–reduction capability of electrons and holes. Z-scheme system is demonstrated to be effective on maximizing the advantages of each photocatalyst. In this work, a novel Z-scheme heterojunction photocatalyst containing TiO2 nanofilm, Carbon Quantum Dots (CQDs) and Cd0.5Zn0.5S (CZS) nanoparticles (CZS/C/TiO2 nanofilm) was fabricated by hydrothermal method and an in situ reflux reaction process. The existence of CQDs results in a direct combination of electrons and holes from the CB of TiO2 and VB of Cd0.5Zn0.5S, and retains the active electron and holes in this system. Besides, it also benefits from the excellent optical absorption and prolonging electron lifetime, the ternary system shows excellent activity during photocatalytic water splitting with a high H2 production rate of 38.74 mmol·h − 1·m − 2, which is 3.4 and 1.5 times higher than that of pure TiO2 and CZS/TiO2 type II heterojunction without CQDs. In addition, CQDs bridged semiconductors as all solid-state Z-scheme heterojunction exhibit good stability and reusability.

Construction of TiO2/silane nanofilm on AZ31 magnesium alloy for controlled degradability and enhanced biocompatibility

A TiO2 nanofilm was prepared on the surface of AZ31 magnesium alloy with controllable thickness through atomic layer deposition (ALD) technique, which can adjust the corrosion behaviors of AZ31 Mg alloy. Compared with the untreated Mg alloys, corrosion current densities (icorr) can decline by 58% in the 200-cycles TiO2-covered Mg alloy and further decline by up to 74% with the thickness of nanofilm up to 63 nm (400 cycles). The subsequent modification with a cross-linked conversion layer of 3-amino-propyltriethoxysilane (APTES) by a dipping method can produce a compact silane coating on TiO2 nanofilm, which can seal pinholes of TiO2 nanofilm and serve as a barrier to further adjust the corrosion behavior of the substrate. The icorr can decline about two orders of magnitude in the TiO2/silane composite coating. Making the adjustable corrosion rate come true, which can be attributed to the precise control on the thickness of metal oxide nanofilm and additional protection from the compact silane coating. In vitro study discloses that the TiO2/silane hybrid coating shows higher expression of alkaline phosphatase (ALP) and can promote cellular adhesion and proliferation with better cytocompatibility than untreated Mg alloy.

Color stability of maxillofacial prosthetic silicone functionalized with oxide nanocoating

Statement of problemMaxillofacial prostheses made of silicone elastomers undergo undesirable color degradation over time. How this color change can be prevented is unclear. PurposeThe purpose of this in vitro study was to evaluate the ability of an oxide nanocoating to prevent color degradation of maxillofacial silicone elastomers after artificial accelerated aging. Material and methodsA silicone elastomer with functional intrinsic pigment was tested. Specimens (N=20) were fabricated, and half of them were coated with a nanolayer of titanium dioxide (TiO2) using atomic layer deposition. Both coated and noncoated specimens (control) were exposed to artificial aging at 450 kJ/m2 of total energy. Changes in the color of all the specimens with and without TiO2 nanocoating were measured before and after the atomic layer deposition coating and before and after aging. The obtained color data were analyzed by using independent t tests and the 1-sample t test (α=.05). ResultsColor change (ΔE1=3.4 ±1.4) was observed for the silicone elastomers after the specimens were surface coated with TiO2 nanofilm, although this change was not statistically significant (P=.369) compared with the acceptability threshold (ΔE=3.0). Upon exposure to artificial aging, the noncoated control specimens underwent color change (ΔE2=2.5 ±0.7, P=.083 compared with the acceptability threshold). The specimens with TiO2 nanocoated surface experienced the least color change (ΔE3=1.4 ±0.6) when subjected to artificial aging, and this change was significantly lower (P<.001) than the established acceptability threshold of ΔE=3.0. In addition, the chemical analyses confirmed that the TiO2 nanocoating remained on the surface after exposure to artificial aging. ConclusionsTiO2 nanocoating was shown to be effective in reducing color degradation of the silicone elastomer exposed to artificial aging for 120 hours with 450 kJ/m2 of total energy.

Photocatalytic Activity and Photodegradation Rate Constant of Au-TiO2 Nanofilms by Magnetron Sputtering

Au-TiO2 nanofilms were prepared on indium-tin oxide glass by magnetron sputtering. The growth of well-aligned Au/TiO2 nanofilms arrays by magnetron sputtering was presented for the first time. The Au/TiO2 nanofilms were grown on the surface of indium tin oxide (ITO) substrates. The photocatalytic activity of the prepared Au-TiO2 nanofilms in an aqueous solution of methylene blue (MB) was evaluated under the irradiation of visible-light. The experimental results show that the use of Au in TiO2 nanofilms improves photocatalytic activity of the MB organic compound significantly in the aqueous solution under the irradiation of visible light, and the photodegradation rate constants of the prepared Au/TiO2 nanofilms for the photodegradation of MB are larger than that of pure TiO2 nanofilms.

Effects of proton irradiation on structures and photo-catalytic property of nano-TiO2/CNTs films

Thin nano-TiO2 films were prepared using aqueous SILAR (successive ionic layer adsorption and reaction) technique on the carbon nanotubes (CNTs) films using titanium trichloride and water as precursors. TiO2-deposited carbon nanotubes (TiO2/CNTs) films were irradiated with 120 keV proton beam, and then analyzed using Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and photocatalytic degradation tests. The results indicate that irradiation could transfer the amorphous deposited TiO2 films to a crystalline state, while the CNTs substrate would also be damaged, namely CNT tube diameter shrinkage and the Raman peak ratio of ID/IG decreases with increasing proton fluences. It was also found that the TiO2 modification could result in more damage to the CNTs substrate as the proton fluence is lower. This is largely due to the fact that the process of activation before deposition could cause damage to the CNTs to some degree. It is interested to be noted that proton irradiation would induce the nano-TiO2/CNTs films to show the remarkable photocatalytic degradation behaviors using methylene blue as the test additive. Moreover, the case with thinner TiO2 on CNTs appears relatively better photocatalytic degradation behaviors. The reasons for the change of photocatalytic behaviors may be due to both crystallization of TiO2 layers and carrier trapping effect of CNTs.

Enhanced lithium storage properties of graphene-based metal oxides by coating with amorphous TiO2 nanofilms

Integration of metal oxides with graphene can highly improve their electrochemical performance as promising anode materials for lithium-ion batteries. However, the pulverization, expansion and detachment of metal oxide particles on graphene are still present and lead to the performance degradation after long-term cycling. In this work, TiO2 nanofilms-coated graphene-SnO2 and graphene-Fe2O3 are prepared and exhibit exceptional electrochemical performance, especially great cycling stability, because amorphous TiO2 nanofilms can prevent the pulverization, expansion and detachment of SnO2/Fe2O3 nanoparticles on graphene, and increase the flexibility and mechanical strength of graphene hybrid electrodes. Moreover, it is apt to form thin and stable solid-electrolyte interphase layers on the surface of TiO2 nanofilms rather than the graphene substrate. Accordingly, this novel and facile synthetic procedure offers great promise for the development of high-performance graphene hybrids utilized in various applications such as batteries.

Community Refinery Wastewater Photodegradation by Fe-Doped TiO2 Films

Photocatalytic treatment of real community wastewater using Fe-doped TiO2 nanofilm was prepared by modified sol-gel method together with a simple dip-coating technique. The process was investigated in a home-made batch photoreactor. The as-prepared nanocomposite film was characterized by UV-Vis diffuse, XRD, BET, and Fe-SEM analysis. The poultry processing wastewater was collected from Nakhonsawan Municipality. Subsequently, the photocatalytic treatment of the wastewater was performed using a home-made photoreactor operated in batch mode to demonstrate the effects of Fe-dopant concentration with various layer numbers. The catalysts were irradiated using four lamps of 15 W power that emitted visible light and performed at room temperature. The samples were collected every 15 min and analyzed for biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal efficiency compared to pure TiO2 nanofilm and direct photolysis. From the results, the mixture of rutile and anatase was obtained with the maximum specific surface area of 150.12 mg2/g and the average particle size of 39.95 nm for 3 layers of 0.15% wt/v Fe-doped TiO2. The BOD and COD value at 90 min time treatment was presented to be 8.87 and 32 mg L−1, respectively, in the presence of 0.15% wt/v Fe-doped TiO2 film photocatalysts. Moreover, atomic absorption spectrometric result ensured that no Ti contamination was detected in all parts of plants after watering by the treated water. Hence, the photocatalytic treatment markedly improved the quality of the community wastewater.

Photocatalysis electroless plating of copper pattern on Al2O3 ceramic substrate combined with template shape control method

ABSTRACTA convenient and efficient approach for copper pattern preparation on Al2O3 ceramic substrate has been developed. The anatase nano-TiO2 film was firstly deposited on the surface of Al2O3 ceramic substrate to provide electron-hole pairs in subsequent photocatalysis electroless copper plating (PECP), and then PECP combined with template shape control method was initiated by ultraviolet light to fabricate the desirable conductive pattern. A continuous copper pattern layer could be obtained by controlling the electroless plating process during PECP. A low resistivity of about 3.49 × 10−8 Ω·m of the copper layer was achieved, which was only about 2 times higher than that of pure copper. Moreover, such a copper layer exhibited satisfactory smoothness with roughness of Ra 472 nm and reliable adhesion with bonding strength of higher than 37 MPa to substrate. This approach proposes a potential way to realize selective surface metallization on ceramic substrates without high temperature and any sophisticated equipment.

Well-Aligned Au/TiO₂ Nanorods by Magnetron Sputtering with Enhanced Photocatalytic Properties.

In this work, we demonstrate the feasibility of preparing Au/TiO2 nanorods via a dc magnetron sputtering at room temperature and heat-treatment at 500 °C in air for 2 h. The heat treatment leads to the migration of Au atoms into TiO2 nanofilm to form Au/TiO2 nanorods with Au nanoparticles embedded in the TiO2 nanorods of anatase phase. The Au nanoparticles in the TiO2 nanorods suppress the charge recombination. These Au/TiO2 nanorods showed high absorption and intensive response to the visible light and had improved photocatalytic properties in comparison with pure TiO2 nanoparticles formed by using similar method.

EFFECT OF ELECTROLYTE SOLUTION ON STRUCTURAL AND OPTICAL PROPERTIES OF TiO2 GROWN BY ANODIZATION TECHNIQUE FOR PHOTOELECTROCATALYTIC APPLICATION

In this work, TiO2 nanotube thin films were prepared by using the anodization technique. Different electrolytes solutions were used to specify the optimum condition. Annealing in air at different temperatures of (400, 500, and 600)[Formula: see text]C at constant time of 1[Formula: see text]h was achieved for all films. The structure (XRD, SEM, EDX, and AFM), and optical (UV–Visible spectroscopy, PL spectroscopy, and Spectral Response) properties of nanotube TiO2 films were investigated and analyzed for different electrolyte solutions. XRD analysis of all deposited films has confirmed the formation of polycrystalline-tetragonal phase (anatase, and rutile) with increase in crystalline size and, annealing temperatures. SEM measurements of TiO2 films show nanotube shapes with outer diameter of (80–130) nm. EDX analysis confirmed the stoichiometry ratio between Ti and O to be 1:2 to produce TiO2 film. PL measurement results show two peaks: one located at UV-region pointing to energy band gap (Eg) for TiO2 nano films; the second one is located at visible region pointing to impurities on films. Spectral response measurements show photocurrent peaks centered at UV-region (355[Formula: see text]nm). Then, TiO2 films were deposited with different electrolyte solution for photoelectrocatalytic (PEC) application. The higher response to UV-light was received by using TiO2 film grown by anodization technique with (HNO[Formula: see text][Formula: see text]HF) electrolyte solution.

Facile preparation of honeycomb-structured TiO2 nanofilm via breath figures assembly and coffee ring effect

Honeycomb-like porous TiO2 nanofilm was facilely prepared by a two-step self-assembly method. Firstly, a breath figure process was conducted to form an ordered composite film with micro-sized titanium salt particles in the polymer honeycomb holes. Secondly, the inorganic particles disintegrated into nano-sized particles and dispersed in water when a water drop was placed on the surface. The evaporation of water led to the formation of a “coffee ring”, with a very thin layer of TiO2 precursor on the polymer film. A honeycomb-structured TiO2 nanofilm was obtained after calcination.

Fabrication of Visible-light Responsive N-doped TiO2 Nanothin Films via a Top–down Sol–gel Deposition Method Using NH4TiOF3 Single Crystals

We report a novel coating method for TiO2 anatase thin-film fabrication via a top–down sol–gel deposition method using NH4TiOF3 single crystals. A cationic nitrogen-rich porphyrin compound was used to fabricate N-doped TiO2 nanofilms that showed highly efficient photocatalytic activity under visible-light irradiation.

Well-aligned Au/TiO 2 Nanorods Arrays for the Photodegradation of MB by Magnetron Sputtering

Abstract The growth of well-aligned Au/TiO2 nanorods arrays was performed by magnetron sputtering. The feasibility of preparing Au/TiO2 nanorods was demonstrated via dc reactive magnetron sputtering at room temperature and heat-treatment at 500 °C in air for 2 h. The results show that the heat treatment leads to the formation of Au/TiO2 nanorods with Au nanoparticles embedded in the TiO2 nanorods of anatase phase. These Au/TiO2 nanorods show lower photoluminescence emission intensity and higher absorption and intensive response to the visible light, compared with traditional TiO2 nanofilms fabricated by the traditional method. The Au nanoparticles in the TiO2 nanorods suppress the charge recombination.

Resistive switching characteristics and resistive switching mechanism of Au/TiO2/FTO memristor

Resistance random access memory is regarded as one of the most promising candidates for the future nonvolatile memory applications due to its good endurance, high storage density, fast erase speed and low power consumption. As one of the most important transition-metal oxides, the anatase TiO2 has received intense attention due to its inexpensive cost, strong optical absorption, favorable band edge positions and superior chemical stability. In the last decade, the nanometer-sized TiO2 has been shown to exhibit a wide range of electrical and optical properties, such as nanoscale electronics and optoelectronics, which rely mainly on the unique size and shape. Recently, various anatase TiO2 based devices such as the anatase TiO2 nanotube based memristor and the anatase TiO2 nano-film based memristor have been intensively studied due to their nonvolatile resistive switching performances. Furthermore, many conduction mechanisms have been used to elucidate the resistive switching behaviors of the anatase TiO2 based devices. However, the direct growth of anatase TiO2 nanowire arrays (NWAs) on the FTO substrate is still a challenge since there exists a large lattice mismatch of about 19% between the anatase TiO2 NWAs and the FTO substrate. Moreover, the Au/TiO2/FTO based device has not been reported and the resistive switching mechanism of the anatase TiO2 NWAs based memristor is still unclear. In this work, the anatase TiO2 NWAs with (101) preferred orientation are successfully grown on the FTO substrate by a facile one-step hydrothermal process. The resistive switching characteristics and resistive switching mechanism of the as-fabricated Au/TiO2/FTO memristor are investigated systemically. The result indicates that the Au/TiO2/FTO memristor exhibits nonvolatile bipolar resistive switching behavior. Meanwhile, the resistance ratio between high resistance state and low resistance state exceeds 20 at 0.1 V, which can be maintained over 103 s without significant degradation. In addition, the conduction mechanism of the low resistance state is governed by the ohmic conduction mechanism, while the trap-controlled space charge limited current conduction mechanism dominates the high resistance state. The resistive switching model of the Au/TiO2/FTO memristor is developed, and the resistive switching mechanism could be attributed to the formation and rupture of the conductive filaments relating to the localized oxygen vacancies. It demonstrates that the Au/TiO2/FTO memristor may be a potential candidate for the future nonvolatile memory applications.

From Structural Colors to Super-Hydrophobicity and Achromatic Transparent Protective Coatings: Ion Plating Plasma Assisted TiO&lt;sub&gt;2&lt;/sub&gt; and SiO&lt;sub&gt;2&lt;/sub&gt; Nano-Film Deposition

The implementation of the Ion Plating Plasma Assisted technology in the area of surface functionalization for structural color and relic preservation applications is presented. Interferometric structural colors on irregular bumped Titanium surfaces and transparent and achromatic nano films on ancient ceramic artifact have been investigated. Titanium metal and ceramic supports have been utilized for the surface functionalization tests: A metallic electron beam additive manufactured Titanium component and an ancient tile of the XIX century, which was characterized by strong chromatic valence and by a mixed porous and glazed surfaces, have been considered. A reactive magnetron sputtering Ion Plating Plasma Assisted apparatus operating in Argon or Oxygen atmospheres for TiO2 and SiO2 deposition has been utilized. Preliminary tests with two plasma treatments were carried out for optimal processing conditions definition. TiO2 nano-film deposition on irregular Ti surfaces has generated light direction depending color-changing surfaces while good achromatic and transparent coatings were obtained by using SiO2 coating. The high processing flexibility of the Ion plating technology is discussed. The SiO2 IPPA surfaces treatment resulted more convenient for restorative and preservation ancient historical tile was used to finally test the optimized process with Ion Beam Electron Microscopy, which was carried out on the tile porous structure, confirmed the high flexibility and efficiency of the innovative IPPA technology.