Tin Dioxide

Iron-doped tin dioxide nanoparticles Sn1-xFexO2 (0% ≤ x ≤ 10% ), were prepared by coprecipitation method. X-ray diffraction (XRD) patterns indicate that Sn1-xFexO2 nanoparticles (NPs) crystallize in the tetragonal rutile-like structure. Scanning Electron Microscope (SEM) observations did not show more modification of the SnO2 morphology with Fe addition. All the results are consistent with the fact that Fe is strongly soluble in SnO2 host. The optical band gap energy decreased from 3.65 to 3.30 eV with increasing the iron doping concentration in the solution. Finally, the photocatalytic efficiency of Fe0.05Sn0.95O2 nanoparticles (NPs) was examined for the degradation of MB in aqueous solution under UV irradiation. It was found that smaller bandgap of Fe doped SnO2 photocatalyst resulted in a prominent increase in photocatalytic activity of nanoparticles against Methylene Blue (MB) under UV irradiaion.

In the current research work, bismuth doped tin-dioxide (Bi-SnO2) was prepared by wet chemical co-precipitation method. The synthesized material was used as a photocatalyst in the degradation of congo red dye (CR) in its aqueous solution. The prepared catalyst was used in the uncalcined- and calcined forms for the photocatalytic reaction. The synthesized catalyst in both forms was characterized by UV-visible spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD revealed that the calcination of the Bi-SnO2 improved its crystallinity. The SEM showed that the Bi-SnO2 had average size less than 150nm. Photocatalytic degradation of CR dye was carried out under ultra-violet light as well as under sunlight. While testing the photocatalytic degradation performance, it was found that more than 80% of the CR was degraded by using Bi-SnO2 nanoparticles under both lighting conditions. Moreover, the calcined Bi-SnO2 nanoparticles showed better photocatalytic perfo...

Current study reports a rapid one-pot non-hydrolytic condition in the synthesis of SnO 2 QDs nanopowder using tin (II) stearate (Sn(St) 2 ) as environmentally-benign organometallic precursor, which is an unprecedentedly employed-compound in preceding SnO 2 nanopowder productions. The as-synthesized SnO 2 QDs that are hydrophobic can be easily transferred from organic solvent to aqueous solution through a robust ligand exchange method. The stearate-capping ligands on the surface of QDs can be replaced by beta-cyclodextrin ( β-CD) and eventually render the QDs highly water soluble, which ultimately make it exhibit bi-functionality for different liquid medium applications. Structural characterizations reveal that the bi-functional QDs are indeed well-matched with the standard rutile SnO 2 cassiterite phase without the presence of any impurities. The QDs can be interchangeably used as photocatalyst for both aqueous and non-aqueous phase, where it shows significant enhancement of hydrogen gas production as compared to that of commercial SnO 2 nanopowder.

Herein, we report, a simple breath sensor based on Au/PVDF nanocomposites. Au nanostructures have been synthesized by using a simple seed mediated growth method. The synthesized Au nanostructures exhibited uniform spherical morphology with average diameter ~20 nm, confirmed by FESEM analysis. The synthesized nanostructures were further used to form nanocomposites with Polyvinylidene Fluoride (PVDF). The synthesized Au nanospheres as well as Au nanospheres/PVDF nanocomposites were tested for breath analysis. The nanocomposite materials were found to sense breath and uniform breathing patterns were generated. During breathing over sensor, voltage gets generated. The maximum voltage obtained was around 280 mV in breathing cycle.

Nanostructured tin dioxide was synthesized by making use of the catalytic activity of silicatein-α. TEM, HRTEM, and XRD revealed the formation of cassiterite SnO 2 . Surface bound silicatein retains its biocatalytic activity. This was demonstrated by immobilizing silicatein on glass surfaces using a histidine-tag chelating anchor. The subsequent deposition of SnO 2 on glass was monitored by quartz crystal microbalance (QCM) measurements and scanning electron microscopy (SEM). This new aspect of silicatein activity toward the formation of metal oxides other than SiO 2 , TiO 2 , and BaTiO 3 opens up new vistas in composite material synthesis.

A composite powder of tin oxide (SnO 2 ) and silver (Ag) clusters was prepared by a simple and cost effective method of reducing their aqueous mixture with sodium borohydride (NaBH 4 ). Gas sensors based on the composite were made by powder pressing procedure and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrical conductivity and gas sensing behavior of the sensors for methane (CH 4 ) gas were studied as a function of Ag concentration (0.3, 0.5, 0.8 and 1.5 wt%). The Ag additive is found to improve sensor response and widen its working temperature range with notable sensor response. The best sensor response was achieved by the sensor with 0.5 wt% Ag. The enhanced response was proved to be due to both electrical and chemical mechanisms.

To achieve high-performance perovskite light-emitting diodes (PeLEDs), an appropriate functional layer beneath the perovskite emissive layer is significantly important to modulate the morphology of the perovskite film and to facilitate charge injection and transport in the device. Herein, for the first time, we report efficient n-i-p structured PeLEDs using solution-processed SnO 2 as an electron transport layer. Three-dimensional perovskites, such as CH(NH 2 ) 2 PbI 3 and CH 3 NH 3 PbI 3 , are found to be more chemically compatible with SnO 2 than with commonly used ZnO. In addition, SnO 2 shows good transparency, excellent morphology and suitable energy levels. These properties make SnO 2 a promising candidate in both three-and low-dimensional PeLEDs, among which a high external quantum efficiency of 7.9% has been realized. Furthermore, interfacial materials that are widely used to improve the device performances of ZnO-based PeLEDs are also applied on SnO 2 -based PeLEDs and their effects have been systematically studied. In contrast to ZnO, SnO 2 modified by these interfacial materials shows detrimental effects due to photoluminescence quenching.

Doping transition metals have great potential to enhance the optical and magnetic properties. This work described the synthesis of pure and FexZr 1-x O2 (x = 0.04, 0.08, and 0.12 mol %) nanoparticles, structural, magnetic, photocatalytic, and anti-microbial properties.  According to the results, Fe doping reduced the crystallite size from 29.74 to 7.88 nm. Smaller particles have a higher surface area-to-volume ratio, which can enhance their reactivity. UV-visible spectra, the produced un-doped, and Fe-doped zirconia nanoparticles have a comprehensive band-gap material ranging between 4.6 and 1.6 eV. A smaller band gap allows nanoparticles to absorb light more efficiently which enhances the photocatalytic activity. The diffraction pattern of pure and Iron-doped ZrO2 nanoparticles reveals a tetragonal crystalline phase. The retention of the tetragonal crystalline structure upon doping, despite introducing Fe3+, highlights a unique stability in the material. The SEM micrograph confirms the Pure ZrO2 nanoparticles have a rod-shaped morphology and spherical mixture of spherical and needle-shaped morphology for iron-doped zirconia with various concentrations. The hysteresis loop for pristine zirconia exhibits perfect Ferromagnetism at Room Temperature (RTFM), whereas iron-doped zirconia exhibits superparamagnetic behavior, according to a VSM investigation which offers several advantages in fields like medicine, and environmental remediation In addition, iron doping improves zirconia’s anti-microbial properties.

Recent studies have reported thin films containing a significant fraction of the high-pressure orthorhombic phase of tin dioxide ͑o-SnO 2 ͒. Although the generation of a pure film containing this metastable phase is an important goal, a careful examination of claims to that effect show that this goal remains to be achieved.

We have developed a new facile procedure for manufacturing crack-free crystalline thin films of SnO 2 with a uniform mesoporous architecture and full crystallinity of the walls. The procedure is based on the evaporation-induced self-assembly of pre-hydrolyzed tin oxide precursor directed by a commercially available Pluronic polymer. The precursor sol was prepared by the hydrolysis of tin tetrachloride in the presence of ammonium hydroxide in a mixture of ethanol and butanol. The addition of ammonium hydroxide is necessary for the formation of the tin oxide precursor, which is able to self-assemble into a mesoporous structure. The relative concentration of ammonium hydroxide as well as duration and temperature of the hydrolysis reaction influence significantly the properties of hydrolyzed tin oxide species and the mesostructure assembled from them. The films coated from these precursor solutions and calcined at 300 °C to 400 o C exhibit a well-developed worm-like porosity and high crystallinity.

The fabrication of arrays of silicon nanowires (Si NWs) with well-defined surface coverage using the vapor-liquid-solid process requires a good control of the density and size distribution for the metal catalyst. We report on a cost-effective bottom-up approach to produce Si NWs by a low-temperature deposition technology using plasma-enhanced chemical vapor deposition and tin dioxide (SnO) nanoparticles as the source of tin catalyst. This strategy offers a straightforward method to select specific particle sizes by conventional colloidal techniques, and to tune the surface coverage using a polyelectrolyte layer to efficiently immobilize the particles on the substrate by electrostatic grafting. After a further step of reduction into tin metal droplets using hydrogen plasma treatment, the catalyst particles are used for the growth of Si NWs. This approach allows the prodcution of controlled Si NWs arrays which can be used as a template for radial junction thin film solar cells.

The morphology and some principal details of the crystallographic grain structure of tin dioxide thin (20-300 nm) films obtained from SnCl Ø5H O water solution by spray pyrolysis deposition were studied using scanning electron microscopy (SEM), 4 2 X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. Direct correlation between the pyrolysis temperature and several fundamental nanoscale grain shapes and crystallographic features successively replacing each other with T was shown. These were: (I) separate crystallites with a sphere-like shape (spherulites), existing at 300-350 8C; (II) pyr agglomerated spherulites at Ts350-410 8C; and (III) nanocrystals with regular crystal faceting at Ts410-530 8C. In turn, the nanocrystals can be subdivided into three types of crystal habit: needle or long prismatic, prismatic and pyramidal habits, each of which corresponds to its own temperature range in increasing order. XRD study and crystallographic form analysis of the cassiterite phase allowed us to suggest identification of the grain facets observed in our experiments. An explanation is also suggested for the gas-sensing properties of such films, which are strongly dependent on the crystallographic grain habit {hkl} and may be attributed to surface orientation effects.

The present paper deals with the study of the application of the gas phase condensation method to the synthesis of nanostructured tin oxides (SnO and SnO2). The method consists of the evaporation of a precursor compound (Sn, SnO, SnO2) in an inert gas atmosphere (He) to collect an ultrafine powder. The analysis of the obtained materials by XRD (X-ray diffraction), TEM (transmission electron microscopy) and XPS (X-ray photoelectron spectroscopy) allows us to determine the experimental conditions that produce the best nanostructured ultrafine powders.

Tin dioxide thin films deposited onto a glass substrate were prepared by spray pyrolysis technique, and then doped with different elements which are: Al, Zn, Cu, and Sr by electroplating method, these elements were chosen for their different atomic radii. XRD illustrate that all the films were polycrystalline with a tetragonal rutile structure and a strong preferred orientation of (200) plane. Uv-vis spectrophotometer specters showed that the highest average transmittance of Al/SnO2 film was about 86.77% in the visible region and the Sr/SnO2 film had the highest band gap of 3.95 eV. From the MEB images, the morphological characteristics improved when the SnO2 thin films doped with Al and Zn but the opposite happened when it doped with Cu and Sr. The four-point probe showed that the best sample was for Al/SnO2 because it had the highest electrical conductivity around 692.306 (Ω.cm) -1.

Perovskite halide materials are currently attracting considerable attention owing to their superior optical and electrical properties. This study proposes a reliable process for synthesizing hybrid nanomaterials made of methylammonium tin iodide (MASnI 3 ) submicron spheres and tin dioxide (SnO 2 ) nanowires. Post-fabricated hybrid nanomaterials were investigated for NO 2 sensing properties at 25 °C in the dark. The effect of moisture on the NO 2 sensitivity of this material was investigated. The durability of sensor components using this material was also investigated. In this paper, we also discuss the NO 2 sensitivity mechanism of MASnI 3 /SnO 2 hybrid nanomaterials in detail.

As a new generation of high quality graphene, electrochemically exfoliated graphene is an ideal platform for constructing integrated high-performance nanocomposites as advanced electrode materials for energy storage and conversion devices. To take on a challenge of direct growth of nanoparticles on electrochemically exfoliated graphene with limited oxygen-containing functional groups and its hydrophobic nature, a systematic study is carried out on growth of SnO2 nanocrystallites on the surface of electrochemically exfoliated graphene. The results indicate that these nanocrystals can efficiently grow on the functional group-free surface of electrochemically exfoliated graphene, if the precursor molecules can polymerize into larger molecules and aggregate on electrochemically exfoliated graphene followed by decomposition and phase transformation into the final metal oxide nanocrystallites. Some key factors affecting this non-classical crystal growth are investigated. Addition of a small amount of water in a polar aprotic solvent to stimulate polymerization of the precursor molecules and a solvothermal treatment to facilitate decomposition of the disordered

The polymorphic tin dioxide (SnO 2 ) was synthesized by calcinating the sol-gel mineralized hybrid of the tin source solution (SnCl 4 / ethanol/H 2 O) and the lyotropic liquid crystal of ethyl-cyanoethyl cellulose((E-CE)C)/acrylic acid (AA). The sub-micrometer SnO 2 spheres with bimodal distribution at 370 and 860 nm were obtained after calcinating the hybrid at 400°C for 5 h. When the hybrid was exposed to ultraviolet first and then calcinated the flying-saucer-like SnO 2 was formed. The exposure time was found to influence the morphology of the as-prepared SnO 2 . Except for the spherical and the flying-saucerlike SnO 2 , a small amount of welldeveloped polyhedral SnO 2 was also observed in the as-prepared samples. On this basis, the lyotropic liquid crystal of (E-CE)C/AA afforded a novel route to obtain polymorphic SnO 2 .

A composite powder of tin oxide (SnO 2 ) and silver (Ag) clusters was prepared by a simple and cost effective method of reducing their aqueous mixture with sodium borohydride (NaBH 4 ). Gas sensors based on the composite were made by powder pressing procedure and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrical conductivity and gas sensing behavior of the sensors for methane (CH 4 ) gas were studied as a function of Ag concentration (0.3, 0.5, 0.8 and 1.5 wt%). The Ag additive is found to improve sensor response and widen its working temperature range with notable sensor response. The best sensor response was achieved by the sensor with 0.5 wt% Ag. The enhanced response was proved to be due to both electrical and chemical mechanisms.

Single-crystalline SnO 2 microcubes were grown using the hydrothermal method without any catalyst. X-ray diffraction (XRD) patterns and energy dispersive X-ray (EDX) analysis verified that the cubes are tin dioxide SnO 2 . Their morphology and structure was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and Raman spectroscopy. It is revealed that the cube-shaped SnO 2 crystal have dimension varying from 500 nm to 5 mm as a function of chemical concentration and hydrothermal temperatures regimes. According to TEM results the cube axes are [0 0 1] direction and the side surfaces are {11 0} planes. A growth mechanism of SnO 2 cube-shaped crystals has been proposed.

Nanomaterials based on metal oxides are extensively studied for several applications due to their versatility. Improvements in their performances can be obtained due to specific structural modifications. One possible modification is by doping the crystal structure, which can affect the materials structure and properties, especially in nanosized particles. Electronic features are among the properties that can be modified through the doping process, consequently morphological and optical parameters can also be controlled by this process. In this sense, this review presents some modifications to tin dioxide (SnO2), one the most studied materials, mainly through the doping process and their impact on several properties. The article starts by describing the SnO2 structural features and the computational models used to explain the role of the doping process on these features. Based on those models, some applications of doped SnO2, such as photocatalytic degradation of pollutants, CO2 redu...

Nanosized (3.5-14.0 nm) tin dioxide based powders containing antimony oxide and palladium have been prepared by sonication-assisted simultaneous precipitation. Thick film sensors made with these powders showed good sensitivity towards methane and their resistance values are optimum for practical applications. This contrasts with the film made with the powders prepared without sonication, which showed higher resistance in the ambient.

The tin dioxide (SnO 2 ) films doped with bismuth by means of magnetron sputtering of semiconductor two-phase target and powder BiO 2 as source of Bi were produced. The effect of bismuth dope concentration variation on the microstructure, electrophysical and gas-sensing properties was investigated. It has been found, that films consist of crystalline rods with diameter of 21±2 nm and length of 120±10 nm. Bismuth doping provided decrease in signal timing drift of acetone sensor in analyzed probe. Sensitivity to acetone vapor of the sample derived from targets with 0.01% bismuth oxide concentration increase almost by 10 times (up to 850) in comparison with undoped film at 300°С. Based on the obtained experimental data the mechanism of bismuth dope influence on electrical and gas-sensing properties of produced tin dioxide films was evaluated. Obtained results have shown capability the use of bismuth doped dioxide tin films for development of saturated acetone vapor sensors.

The release of industrial untreated wastewater creates a hazardous impact on the environment. In this regard, the development of environment friendly catalyst is of paramount importance. Here, we report a highly efficient and reusable core-shell TiN/SiO2/Cr-TiO2 (TSCT) photocatalyst which is composed of SiO2-cladded titanium nitride (TiN) nanoparticles (NPs) decorated with Cr-doped TiO2 NPs for the removal of organic contaminant from water. The TiN NPs serve as the main light absorber component with excellent visible light absorption along with Cr-TiO2 NPs. The TSCT shows remarkable improvement in the photodecomposition of methylene blue (MB) over Cr-TiO2 and TiO2 NPs. An efficient structural design is proposed by adopting calcium alginate beads (P-Marimo beads) as transparent scaffold for supporting our TSCT which exhibits floatable nature on the water surface and realizes easy handling as well as excellent reusability for multipurpose water purification. Surprisingly, our TSCT is found to keep its catalytic activity even after the

We have investigated the optical properties of sol-gel thin films of tin dioxide (SnO 2) codoped with Er 3 þ-Yb 3 þ as a function of Yb 3 þ concentration. The Judd-Ofelt model has been applied to absorption intensities of Er 3 þ (4f 11) transitions to establish the so-called Judd-Ofelt intensity parameters: O 2 , O 4 , O 6. Various spectroscopic parameters were obtained to evaluate their dependence and the potential of the samples as a laser material in the eye-safe laser wavelength (1.53 mm) as a function of Yb 3 þ concentration. An amelioration of the quality factor O 4 /O 6 was found with Yb content. Both the IR photoluminescence (PL) intensity and the up-conversion emission, from Er 3 þ ion in SnO 2 , were found to increase with Yb concentration. We show that the Yb 3 þ ion acts as sensitizer for Er 3 þ ion and contributes largely to the improvement of the spectroscopic properties of SnO 2 :Er. The mechanism of up-conversion emission is discussed and a model is proposed. The results showed that sol-gel SnO 2 is promising gain media for developing the solid-state 1.5 mm optical amplifiers and tunable up-conversion lasers.

The complexity of the competition between nonradiative energy transfer and charge transfer is presented in this work. This study uses ZnO nanocrystals as a donor component and rhodamine B (RhB) dye as an acceptor component. Investigations reveal that the concentration of intrinsic defects and their localization, particularly oxygen vacancies, zinc interstitials, and oxygen interstitials, play a vital role in nonradiative energy transfer from ZnO nanocrystals to RhB dye. Additionally, photoluminescent spectra indicate that ZnO nanocrystals degrade the emission signals of RhB dye via charge transfer. It is possible that a part of oxygen vacancies may also contribute to the photocatalytic oxidation of the RhB molecule. The correlation between electron paramagnetic resonance, photoluminescence, and the RhB emission decay rates indicates two processes that one may encounter when dealing with semiconductor-dye conjugates. First is a complex energy transfer from ZnO to RhB indicating a photoluminescent up-conversion and second is a charge transfer from photoexcited intrinsic defect species in ZnO suppressing the RhB emission signals, which occur together. The photoluminescent up-conversion in ZnO+RhB is due to a nonradiative energy transfer from photoexcited zinc interstitials or doubly charged oxygen vacancies in ZnO to RhB. Additionally, the suppression of RhB emission occurs due to charge transfer from oxygen vacancies in ZnO.

The size and shape effects on melting, glass transition, and Kauzmann temperatures of SnO 2 nanoparticles using Lindemann's criterion have been studied. The melting temperature of SnO 2 nanoparticles decreases as the size of the particle decreases. As the particle size increases, melting temperature increases and approaches to the melting temperature 1,903 K of bulk irrespective of the shape. The glass transition and Kauzmann temperatures are analyzed through the size effect on the melting temperature. The glass transition and Kauzmann temperatures decrease with the decrease in size of SnO 2 nanoparticles.

Les températures classiques de fonctionnement de la plupart des capteurs chimiques de gaz sont généralement supérieures à 300°C, ce qui ne représente pas les conditions favorables de leur fonctionnement en termes de stabilité, répétabilité et consommation énergétique. Pour ce, dans ce travail, nous avons développé une nouvelle méthode d’élaboration par voie sol-gel des couches minces à base de dioxyde d’étain(SnO2) sensibles à la détection de l’ozone et de l’ammoniac à température ambiante et à l’état de traces. L’ajustement des paramètres expérimentaux relatifs à ce procédé (solvant, concentration du dispersant, température et temps de recuit,…) a permis d’optimiser les conditions de préparation des couches minces et par la suite de contrôler les caractéristiques chimiques et texturales des couches sensibles développées. Dans cette étude les précurseurs du SnO2 ont été préparés selon deux approches.[...]Les résultats de détection de gaz ont montré qu’à l’inverse des couches élaboré...

In the present work studies have been made to analyze the sensitivity, response of SnO2 based Pd-doped thick film gas sensor for LPG detection using ANN. Thick film SnO2 sensor was fabricated on a 1 x1 alumina substrate. It consists of a gas sensitive layer (SnO2) doped with Pd, a pair of electrodes underneath the gas sensing layer serving as a contact pad for sensor. Also a heater element on the backside of the substrate was printed. The sensitivity of sensor has been studied at different Pd-doped concentrations (1%, 0.25% Pd ...

Tin chloride and Palladium chloride were used to fabricate H2 sensor based on PdO, SnO2 and PdOx functionalized SnO2 nanoparticles. There sensors were fabricated by spin coating technique using single step thermal decomposition method (SSTD) with annealing temperature of 550°C. The chemical composition and microstructure of the obtained samples were characterized by using X-ray diffraction, UV-VIS spectra, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The sensing characteristic of sensors was investigated at different operation temperatures 25, 50 and 80°C. Results showed that PdOx-SnO2 sensor exhibited excellent sensing performance to H2 at room temperature (RT). When the operating temperature was 50°C, the detection limit towards H2 was 0.5 ppm with ultrafast response and recovery time. In addition, the sensor exhibited excellent stability and repeatability at different relative humidity with a high selectivity to H2 detection against CO, CO2, LPG, ace...

SnCl 2 (solution) was spin coated on soda lime glass and Al 2 O 3 substrate to obtain nano-particulate tin oxide film, directly by sintering at 550 • C for 40 minutes (min). The surface morphology and crystal structure of the tin oxide films were analyzed using atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of SnO 2 nanostructure was determined from UV-vis and found to be .3 nm. These films were tested for sensing H 2 concentration of 0.1-1000 ppm at optimized operating temperature of 265 • C. The results showed that sensitivity (R air /R gas per ppm) goes on increasing with decreasing concentration of test gas, giving concentration dependent changes. Special studies carried out at low concentration levels (0.1-1 and 1-10 ppm) of H 2 , give high sensitivity (200 × 10 −3 /ppm) for lowest concentration (0.1-1 ppm) of H 2. The selectivity for H 2 against relative humidity (RH), CO 2 , CO and LPG gases is also good. The sensor, at operating temperature of 200 • C, is showing nearly zero response to 300 ppm of H 2 , and offering response to acetone vapour of 11 ppm. Selectivity for acetone against RH% and CO 2 was also studied. These sensors can be used as H 2 sensor at an operating temperature of 265 • C, and as an acetone sensor at the operating temperature of 200 • C.

photoluminescence in doped tin dioxide [Sn(Ln)O 2 ] and doped titanium dioxide [Ti(Ln)O 2 ] nanoparticles shows that the emission efficiency of trivalent lanthanide cations (Ln 3+) in an oxide matrix can be improved by change of the cation site symmetry. An analysis of Ln 3+ emission quantum yield and asymmetry ratio is used to identify the importance of symmetry breaking around the dopant site for enhancing the Ln 3+ emission intensity. These findings identify an important criterion for engineering the luminescence intensity of dopant ions in semiconductor nanoparticle-based luminophores, which goes beyond the primary criterion of engineering the relative positions of the dopant energy levels with respect to the band edges of the host nanoparticle matrix.

Thick film methane sensors have been fabricated from nanosized tin dioxide powder containing antimony oxide and palladium. The powder has been prepared by sonication-assisted simultaneous precipitation and the sensors made with this powder showed optimum resistance for device applications and good sensitivity towards methane. This contrasts with the thick film sensors prepared with the powder synthesized without sonication, which showed very high resistance at the operating temperature. The complex plane impedance spectroscopy of the sensors (both in air and in the presence of gas) can be a good indicator of the sensor quality. It has been observed that the nature of the complex plane impedance plot of the sensors fabricated by using powders synthesized through sonication-assisted simultaneous precipitation matches well with that of high-quality imported Figaro (Japan) sensors.

Tin dioxide ( SnO 2) thin films were prepared using the thermal spray p yrolysis method from SnCl2.2H 2O isopropyl mixing with water solution on the glass substrate h eated at 450 ◦ C. The films were characterized by X-ray diffractio n (XRD), The crystallite size was evaluated to be 4.4 13 nm by using the Scherrer’s equation. Atomic For ce Microscope (AFM) and optical absorption spectra wer e taken to examine the surface morphology and opt ical properties to determine the band gap energy 3.9 eV, increase in band gap energy is revealed that nan ostructure SnO 2 films. These films were tested in butane gas at op erating temperature 470 ◦ C. The response and recovery time is 13 sec, 63 sec respectively. Keyword: SnO 2 Thin films; spray pyrolysis; butane gas sensing; s ensitivity.

A tin oxide (SnO 2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO 2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO 2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor's prominent sensing properties between SnO 2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.

Characterization of four amalgam surfaces, with different alteration degrees from Andalusia historical mirrors, has been carried out by grazing-incidence X-ray diffraction (GIXRD), and other spectroscopic techniques (SEM/EDX, XPS, and REELS). The combination of all these techniques allows determining the corrosion state of the amalgams. The results show that the amalgams are composed in all cases of a binary alloy of tin and mercury. As mercury has high vapour pressure at RT, it slowly segregates and eventually evaporates, it leaves finely divided particles of tin that easily can be oxidize, forming tin monoxide (SnO) and tin dioxide (SnO2). In one of the samples, most of the amalgam remains unoxidized, since Hg0.1Sn0.9 and metallic Sn phases are the major components; in two other samples, Hg0.1Sn0.9 and Sn phases are not detected while SnO2 and SnO phases appear. Finally, in the last studied sample, only SnO2 phase is detected. The surface analyses of these samples by XPS show that...

Composites consisting of tin and silicon dioxide or antimony and silicon dioxide were synthesized using high energy mechanical milling. The composites were made by the reactive milling of SnO or Sb 2 O 3 with pure Si, resulting in the oxidation of silicon and the reduction of the metal oxides. The minimum time required to complete the reaction for the tin system was 170 min, while the minimum time for the antimony system was 230 min. X-ray diffraction and infrared spectroscopy were used to determine the phases present in the composites. In addition, scanning electron microscopy, along with energy dispersive X-ray analysis (EDX), was used to characterize the microstructure and composition of the resultant material.

In the present paper, tin dioxide (SnO 2 ) thin films had been fabricated with different precursor concentration in the range of 0.01-0.09 M onto amorphous glass substrates utilizing nebulizer spray method. The effect of precursor concentration on electrical, morphological, structural, optical, and photoluminescence properties has been investigated. XRD spectrum revealed that the polycrystalline nature of SnO 2 thin films with tetragonal structure in the range of precursor concentration 0.03-0.09 M, which are having a favorable growth orientation along (110) direction. The estimated average crystallite size varied between 22 and 53 nm. UV-Visible spectrum exposes the transmittance of SnO 2 thin films lies between 90 and 78% in the visible range. The direct band gap energy reduced from 3.83 to 3.71 eV on increasing precursor concentration upto 0.07 M and then it was further increased. Photoluminescence spectra at room temperature exhibited a strong peak at 362 nm with shoulder peak at 376 nm and two broad peaks are 493 nm and 518 nm. SEM analysis illustrated that the polyhedron-like grains were homogeneously arranged over the film surface. The film prepared at 0.07 M precursor concentration shows the least resistivity 2.41 × 10 -3 Ω-cm and good figure of merit 16.41 × 10 -3 (Ω/sq) -1 .

In the present work, we demonstrate that organometallic complexes constitute efficient precursors to design nanostructured Pd-or Pt-doped tin dioxide material. We demonstrate also that this material, under the form of colloidal solutions, can be implemented at an industrial scale as sensitive layer by drop deposition process onto micro-machined silicon substrates. Responses of these sensors to CO, H2 , C3H8 and NO2 are presented and discussed.

Nanocomposite core ± shell particles that consist of a Sn 0 core surrounded by a thin layer of tin oxides have been prepared by thermolysis of [{Sn(NMe 2) 2 } 2 ] in anisole that contains small, controlled amounts of water. The particles were characterized by means of electronic microscopies (TEM, HRTEM, SEM), X-ray diffraction (XRD) studies, photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. The TEM micrographs show spherical nanoparticles, the size and size distribution of which depends on the initial experimental conditions of temperature, time, water concentration, and tin precursor concentration. Nanoparti-cles of 19 nm median size and displaying a narrow size distribution have been obtained with excellent yield in the optimized conditions. HRTEM, XPS, XRD and Mössbauer studies indicate the composite nature of the particles that consist of a well-crystallized tin b core of % 11 nm covered with a layer of % 4 nm of amorphous tin dioxide and which also contain quadratic tin monoxide crystallites. The thermal oxidation of this nanocomposite yields well-crystallized nanoparticles of SnO 2 without coalescence or size change. XRD patterns show that the powder consists of a mixture of two phases: the tetragonal cassiterite phase, which is the most abundant, and an orthorhombic phase. In agreement with the small SnO 2 particle size, the relative intensity of the adsorbed dioxygen peak observed on the XPS spectrum is remarkable, when compared with that observed in the case of larger SnO 2 particles. This is consistent with electrical conductivity measurements, which demonstrate that this material is highly sensitive to the presence of a reducing gas such as carbon monoxide.

The main structure and electronic parameters of SnO thin films are considered from the point of view of optimization gas 2 sensor characteristics. The results of phenomenological modeling and their comparison with experiments are used for choosing the correct film parameters and modes of deposition for the processing of SnO films by the spray pyrolysis method. Optimal 2 deposition conditions were found, allowing one to obtain films with improved sensitivity, selectivity, low temperature sensitivity maximum position and low response times without additional doping by metal catalysts.

We report the successful one pot synthesis of crystalline mesoporous tin dioxide powder doped with fluoride at ambient pressure and temperature. This material possesses a high surface area, narrow pore size distribution, small average crystallite sizes, and good opto-electrical properties. The existence of fluorine increased the opto-electronic activity of tin dioxide by 20 times, and conductivity by 100 times compared with pristine tin dioxide prepared via the same method. The conductivity of SnO2 in air at 25 °C is 5 × 10−5 S/m, whereas that of F–SnO2 is 4.8 × 10−3 S/m. The structures of these materials were characterized with powder X-ray diffraction, N2 sorption analysis, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV-visible spectroscopy. Fluorine occupies the framework of tin dioxide by replacing some of the oxygen atoms. The structure, conductance, and optical properties of these m...

We report the successful synthesis of a new material, a crystalline mesoporous tin dioxide (m-SnO2) framework that contains nanogold clusters (m-SnO2-Au), prepared using a direct soft method under ambient pressure. The structure, bulk, and surface properties of this new material are analyzed and confirmed by N2 adsorption–desorption analysis, powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. The material possesses a high Brunauer–Emmett–Teller (BET) surface area of 97 m2g–1, a narrow pore size distribution (2.1 to 3.3 nm) with an average pore diameter of 2.7 nm, and an average pore volume of 0.06 cm3g–1. We believe that the nanogold clusters initially occupy the pores of the mesoporous tin dioxide, thus restricting their growth before diffusing into the walls of tin dioxide during the second heat treatment. The median nanogold cluster size is 1.4 nm...

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.

As an approach to combat the increasing emissions of carbon dioxide in the last 50 years, the sequestration of carbon dioxide gas in ionic liquids has become an attractive research area. Ionic liquids can be made that possess incredibly high molar absorption and specificity characteristics for carbon dioxide. Their high carbon dioxide solubility and specificity combined with their high inherent electrical conductivity also creates an ideal medium for the electrochemical reduction of carbon dioxide. Herein, a lesser studied ionic liquid, 1‐ethyl‐3‐methylimidazolium trifluoroacetate, was used as both an effective carbon dioxide capture material and subsequently as an electrochemical matrix with water for the direct reduction of carbon dioxide into formate at indium, tin, and lead electrodes in good yield (ca. 3 mg h−1 cm−2).