Papers by Keyword: TiN Dioxide

Abstract: In this study, SnO₂ was successfully synthesized using spray pyrolysis method. Knowing that lanthanides has the capability to enhance the performance of metal oxides in supercapacitor application, Samarium was loaded to Tin Dioxide (SnO2) at different percent weight concentrations (0.5%, 1%, 3% 5%). XRD diffractograms shows the formation of tetragonal rutile structure with prominent peaks at 26.6°, 34.08°, 51.94° that corresponds to (110), (101), and (211) respectively and no additional peaks was detected with the incorporation Sm³⁺ ions which. The data obtained from Energy Dispersive X-ray Spectroscopy confirm the presence of Sm on the spray pyrolyzed SnO2. Scanning electron micrograph revealed that the increase in loading of Sm changes the morphology of the samples from 1D to 2D structures. Faradaic reactions indicated by the oxidation and reduction peaks were monitored using cyclic voltammetry in 1M KOH electrolyte. The specific capacitances were determined by analyzing the galvanostatic charge discharge profile of each sample. SnO₂ with 0.5% Sm yield the the highest specific capacitance, energy density and power density of 54.55 F/g, 1.60 WHr/kg, and 230 W/kg respectively. The results from this research offers a valuable information in synthesizing binder-free electrode and modifying its properties by incorporating samarium. These electrodes can be used for advanced applications such as electrochemical energy storage device, electrochemical sensors, and electrocatalytic applications.

Abstract: Through a simple electrodeposition technique, SnO₂/MnO₂ nanocomposite films were directly deposited onto ultrathin stainless-steel (SS) foils for use in electrochemical supercapacitors. The materials were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Electrochemical experiment revealed that the SnO₂/MnO₂ electrodes exhibited a high gravimetric capacitance of 876 F/g at a current density of 1 A/g. Furthermore, an asymmetric supercapacitor was fabricated using the SnO₂/MnO₂ nanocomposite as the positive electrode and activated carbon as the negative electrode. This asymmetric device demonstrated a capacitance of 72.2 F/g at 1 A/g and retained approximately 87.5% of its initial capacitance after 28,000 cycles, highlighting its excellent cycling stability and practical application potential. The combination of high capacitance and robust stability makes this SnO₂/MnO₂ nanocomposite a promising candidate for high-performance supercapacitor electrodes.

Abstract: In the present paper, a composite containing mixed oxides of tin and lead has been synthesized by the method of pulsed high-voltage discharge. Material was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis and transmission electron microscopy. The composite consists of SnO₂ and PbO particles with an average size of ~350 nm, and SnPb₂O₄ nanowhiskers with size of 100 nm in diameter and few microns in length. The electrochemical performance of nanocomposite as a potential anode of lithium-ion battery has been investigated by the cyclic voltammetry and galvanostatic charge/discharge test in the potential range of 3.0–0.005 V. The reversible capacity of 821 mA·h/g was realized after 5-fold cycling at a current density of 100 mA/g. It was established that further cycling of the material is accompanied by a dramatic capacity fade: only 13 % of the initial capacity was obtained already after 10 cycles. The observed degradation in performance of nanocomposite results from its inability to compensate large lithiation/delithiation-induced volume expansion.

Abstract: The paper is devoted to the study of the influence of surface modification by catalysts on the gas sensitivity of a gas sensor. The sample for the study is a gas sensor crystal with dimensions of 1 × 1 mm², manufactured using microelectronic technology. Its design is represented by a film heater, two sensitive elements (SE) based on tin dioxide with the addition of 1 % at. Si (film thickness = 250 nm, the size of the SE area is 200 x 320 μm²) and contacts for the sensitive layer in the form of an interdigital platinum structure with a distance between contacts of 10 μm. It is established that doping increases the gas sensitivity and lowers the operating temperature.

Abstract: Nanostructured SnO₂ is an attractive anode material for high-energy-density lithium-ion batteries because of the fourfold higher theoretical charge capacity than commercially used graphite. However, the poor capacity retention at high rates and long-term cycling have intrinsically limited applications of nanostructured SnO₂ anodes due to large polarization and ~300% volume change upon lithium insertion/extraction. Here we report the design of SnO₂ nanoparticles, which are synthesized by sol-gel method, with an aim at overcome the above problems for the high-performance reversible lithium storage. The results showed that the mean sizes of SnO₂ particles treated with 6 wt.% ammonia were less than 30 nm, which can store charge with a capacity density as high as ~1888 mAh/g. Even when the discharge rate was increased to 0.5 C, it still retained ~1017 mAh/g.

Abstract: We present a direct soft templating method to synthesise mesoporous tin dioxide network that maintains a porous structure after calcination at 400 °C and 500 °C and has a relatively high BET surface area of 220 and 100 m² g^-1, respectively. TEM, BET and XRD results confirm that both crystal and pore sizes increase as a result of increasing the temperatures during the calcination step. This method is highly reproducible.

Abstract: In this paper, we present an IR spectroscopy study of the molecular and supramolecular structure of the polypropylene fibre, used as a metal nanoparticle carrier, by the example of nanoparticles of tin dioxide. The aim of this work is to investigate the changes in the chemical structure of the polypropylene melt-blown web when modified with the tin dioxide nanoparticles. The paper shows that the metal-oxygen valence vibration bands appear in the IR spectra of modified polypropylene fibrous carriers. At the same time, the carrier material remains stereoregular and possess a helical structure.

Abstract: The influence of humidity on the electrical and gas-sensitive characteristics of H₂ sensors based on thin films SnO₂ with deposited Pt/Pd disperse layers (Pt/Pd/SnO₂:Sb) and with the additions of gold in the bulk and on the surface (Au/SnO₂:Sb, Au) has been studied. The time dependences of the conductivity G(t) of sensors operating in pure air and in gas mixture containing hydrogen (air + H₂) in thermo-cyclic operation modes were measured. It was shown that the conductance of films increases and the response to H₂ decreases with an increase in the relative humidity from 10 to 70 %. In the sensors based on thin films Pt/Pd/SnO₂:Sb exposed to hydrogen the over – barrier component of conductivity plays a decisive role. In case of the films modified by gold the channel component of conductivity is prevailing. The role deposited catalysts Pt/Pd and additives of gold in the process of adsorption of water molecules and hydrogen on the surface of tin dioxide is discussed.

Abstract: Nanostructured composites based on titanium dioxide have been studied in order to improve optical and photo-catalytic properties, as well as their performance in gas sensors. In this work, titanium and tin dioxides were simultaneously synthesized by the polyol method resulting in TiO₂ platelet coated with SnO₂ nanoparticles as was observed by scanning electron microscopy. The thermal analysis showed that the combined synthesis promotes more easily the crystallization of the TiO₂ rutile phase. The composite obtained after heat treatment at 500 °C showed to be formed of almost only rutile phases of both oxides. The optical properties analyzed by UV-Vis spectroscopy showed that the combined oxides have higher absorbance, which reinforces a model found in the literature based on the flow of photo-generated electrons to the conduction band of SnO₂ delaying the recombination of charges.

Abstract: TiO₂/SnO₂ thin films heterostructures are grown by the sol-gel-dip-coating technique. It was found that the crystalline structure of TiO₂ depends on the annealing temperature and the substrate type. TiO₂ films deposited on glass substrate, submitted to thermal annealing until 550°C, present anatase structure, whereas films deposited on quartz substrate transform to rutile structure when thermally annealed at 1100°C. When structured as rutile, this oxide semiconductor has very close lattice parameters to those of SnO₂, making easier the heterostructure assembling. Electrical properties of TiO₂/SnO₂ heterostructure were evaluated as function of temperature and excitation with different light sources. The temperature dependence of conductivity is dominated by a deep level with energy coincident with the second ionization level of oxygen vacancies in SnO₂, suggesting the dominant role of the most external layer material (SnO₂) to the electrical transport properties. The fourth harmonic of a Nd:YAG laser line (4.65eV) seems to excite the most external layer whereas a InGaN LED (2.75eV) seems to excite electrons from the ground state of a quantized interfacial channel as well as intrabandgap states of the TiO₂ layer.