SnO2 Nanopowders Research Articles

Synthesis of ZnO-decorated SnO2 nanopowder with enhanced photocatalytic performance

In recent years, heterogeneous photocatalysis has been paid much attention in the world as an important technique for treating wastewater. In this study, ZnO-decorated SnO2 nanopowders were prepared by hydrothermal method, and the effect of ZnO addition on the photocatalytic activity of SnO2 powder was investigated. The structure and morphology of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The composition was determined by X-ray photoelectron spectroscopy (XPS). The recombination behavior of photogenerated electrons and holes was studied by photoluminescence. The photocatalytic activity of the samples was tested by degradation of methylene blue (MB) which was used as a simulated organic pollutant. The experimental results show that compared with pure ZnO and SnO2 powders, the particle size of ZnO-SnO2 composites is reduced, photoluminescence is weakened, but the photocatalytic activity is improved. The enhancement in photocatalytic activity is attributed to the increased specific surface area due to the decrease of particle size and the formation of ZnO-SnO2 heterojunction which inhibits the recombination of photogenerated electrons and holes.

Self-cleaning and weather resistance of nano-SnO2/modified silicone oil coating for photovoltaic (PV) glass applications

The current investigation focused on the development of a new class of transparent nano-SnO2/modified silicone oil based coating with hydrophobic behavior and excellent self-cleaning properties for photovoltaic (PV) applications. SnO2 nanopowder was blended with silicon oil using isopropyl alcohol as a solvent which was then applied on the glass substrates using sponges. The treated glass plates were then subjected to water contact angle (WCA) measurement in order to determine the hydrophobicity of the modified glass. The results revealed the high WCA of 118° ± 2° displaying enhanced hydrophobic characteristic whereas, the UV–Vis analysis demonstrated an improved transmittance (99%) in visible region. Moreover, the prepared-coating also exhibited an excellent anti-fogging and wear-resistance behavior and was found to have insignificant changes in the WCA for 20 peeling cycles using scotch tape. Outdoor exposure’s results also confirmed that the nano SnO2–silicone oil coating on the glass panel possess superior durability against weather with WCA was 110° ± 2° and transparency > 92% in visible region even after 2 months of outdoor exposure.

TiO2, SnO2 and ZnO catalysts supported on mesoporous SBA-15 versus unsupported nanopowders in photocatalytic degradation of methylene blue

Abstract Semiconductor metal oxides (TiO2, ZnO or SnO2) deposited on a highly ordered mesoporous silica material (called SBA-15 in the literature) were compared for the first time as photocatalysts in the elimination of cationic methylene blue (MB) dye from neutral aqueous solutions by adsorption and/or photodegradation under ultraviolet (UV) irradiation. Prepared catalysts were characterized by N2 physisorption, X-ray diffraction, UV–visible diffuse reflectance spectroscopy, ammonia temperature-programmed desorption, isoelectric point determination, scanning and transmission electron microscopy. Characterization results showed that the mesoporous structure of the SBA-15 was preserved in the catalysts. However, the dispersion of metal oxides in the catalysts was very different. Zinc oxide was well-dispersed in the ZnO/SBA-15 catalyst, whereas TiO2 and SnO2 crystalline phases were detected in the TiO2/SBA-15 and SnO2/SBA-15 samples, being SnO2 oxide the worst-dispersed. All SBA-15-supported catalysts showed high capacity for MB adsorption, especially the ZnO/SBA-15 one, and had a significantly higher (2–5 times) photocatalytic activity than the corresponding commercial TiO2, ZnO and SnO2 nanopowders. The TiO2/SBA-15 and ZnO/SBA-15 catalysts resulted in a higher degree of mineralization of MB dye (63%) than titania Degussa P25 (39%) in the photocatalytic degradation of MB after the adsorption step. This was attributed to the higher specific surface area of the SBA-15-supported catalysts, their higher adsorption capacity and better dispersion of the supported metal oxides in comparison with titania P25. In addition, deposition of ZnO on the SBA-15 surface prevented the photocorrosion of ZnO that is an important advantage compared to pure ZnO nanoparticles.

Tin Oxide Based Nano Electroceramics Obtained from Sol–Gel Process: The Modified of the Structural and Opto-Electrical Properties with the Al Doping

Nano electroceramic samples of undoped and Al doped SnO2 were synthesized by the sol–gel calcination process. The structural, morphological, electrical and optical properties of samples were characterized. X-ray diffraction analysis results confirm that all of the synthesized nanopowders are polycrystalline with a tetragonal structure. The crystallite size values of the prepared nanocomposites were calculated in the range of 21.32–34.33 nm. The values of crystallite size indicate that the prepared powders have nanostructure. The grain size and morphological parameters of the undoped and Al-doped SnO2 nanopowders calculated. AFM measurements suggest that Al dopants ratio could be an effect to control surface parameters of the SnO2 nanomaterials. The optical band gap (Eg) of prepared nanomaterials were calculated using Tauc plot method for the various atomic ratios of Al. The calculated Eg values for samples are found to be in the range from 3.51 to 3.69 eV. The electrical conductivity of undoped and Al doped Tin oxide nanopowders were carried out at the temperature range from 290 to 420 K. It demonstrates that the electrical conductivity at room temperature and the activation energy of samples increase with the Al doping. The obtained results suggest that the structural, morphological, optical and electrical properties of SnO2 based nanomaterials can be controlled and changed with Al content.

Thermal Calcination-Based Production of SnO₂ Nanopowder: An Analysis of SnO₂ Nanoparticle Characteristics and Antibacterial Activities.

SnO2 nanoparticle production using thermal treatment with tin(II) chloride dihydrate and polyvinylpyrrolidone capping agent precursor materials for calcination was investigated. Samples were analyzed using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), diffuse UV-vis reflectance spectra, photoluminescence (PL) spectra and the electron spin resonance (ESR). XRD analysis found tetragonal crystalline structures in the SnO2 nanoparticles generated through calcination. EDX and FT-IR spectroscopy phase analysis verified the derivation of the Sn and O in the SnO2 nanoparticle samples from the precursor materials. An average nanoparticle size of 4–15.5 nm was achieved by increasing calcination temperature from 500 °C to 800 °C, as confirmed through TEM. The valence state and surface composition of the resulting nanoparticle were analyzed using XPS. Diffuse UV-vis reflectance spectra were used to evaluate the optical energy gap using the Kubelka-Munk equation. Greater calcination temperature resulted in the energy band gap falling from 3.90 eV to 3.64 eV. PL spectra indicated a positive relationship between particle size and photoluminescence. Magnetic features were investigated through ESR, which revealed the presence of unpaired electrons. The magnetic field resonance decreases along with an increase of the g-factor value as the calcination temperature increased from 500 °C to 800 °C. Finally, Escherichia coli ATCC 25922 Gram (–ve) and Bacillus subtilis UPMC 1175 Gram (+ve) were used for in vitro evaluation of the tin oxide nanoparticle’s antibacterial activity. This work indicated that the zone of inhibition of 22 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175.

Structural and optical properties of Sb doped SnO2 nanopowders synthesized by nebulized spray pyrolysis

Nebulized spray pyrolysis (NSP) was used to synthesize Sn1-xO2: Sbx (x=0, 0.03, 0.06, 0.09) nanopowders in reasonable quantities by making use of low-cost precursors. Structural analysis was carried out by XRD, TEM, SEM and XPS. X-ray diffraction analysis confirmed the formation of phase-pure SnO2 with Sb being incorporated into the crystal structure. Rietveld refinement was used to estimate the lattice parameters and by adopting spherical harmonics, the crystallite sizes were calculated. Transmission electron microscopy revealed that the as-synthesized powders had good crystallinity with particle sizes in the range of 5-15 nm, which was in accordance with crystallite sizes calculated from Rietveld refinement.XPS confirmed the presence of antimony in the doped samples. Optical transparency was evaluated by absorption spectroscopy, which revealed both pure and doped SnO2 to have more than 80% transparency in the visible regime. The band gap energies were estimated from standard Tauc plots.

Vacancy-like defects in nanocrystalline SnO2: influence of the annealing treatment under different atmospheres

The study of electronic and chemical properties of semiconductor oxides is motivated by their several applications. In particular, tin oxide is widely used as a solid state gas sensor material. In this regard, the defect structure has been proposed to be crucial in determining the resulting film conductivity and then its sensitivity. Here, the characteristics of vacancy-like defects in nanocrystalline commercial high-purity tin oxide powders and the influence of the annealing treatment under different atmospheres are presented. Specifically, SnO2 nanopowders were annealed at 330 °C under three different types of atmospheres: inert (vacuum), oxidative (oxygen) and reductive (hydrogen). The obtained experimental results are discussed in terms of the vacancy-like defects detected, shedding light to the basic conduction mechanisms, which are responsible for gas detection.

Improved photodegradation activity of SnO2 nanopowder against methyl orange dye through Ag doping

Silver doped tin oxide (SnO2:Ag) nanopowders were synthesized by a simple soft chemical route with 0, 5, 10 and 15 wt% concentrations of Ag. The structural, morphological, optical, photoluminescence and photocatalytic properties of the synthesized samples were studied and the results obtained are reported in this paper. XRD studies confirm the polycrystalline nature of the synthesized samples. The undoped and doped samples exhibit a strong (1 0 1) preferential growth. Decreased crystallite size is observed with Ag doping. Nanosized grains were observed for the doped samples. Peak related to Sn–O–Sn lattice vibration is observed for both the undoped and doped samples in the FTIR spectra. Peaks related to oxygen vacancies were observed at 362 and 499 nm for all the samples in the PL spectra. Enhanced photocatalytic activity was observed for the doped samples and the SnO2:Ag nanopowder with 10 wt% Ag doping concentration exhibited maximum photodegradation efficiency against the degradation of methyl orange dye.

PbS–SnO2 nanocomposite with enhanced magnetic, photocatalytic and antifungal properties

A cost effective chemical route is used to synthesize pure PbS, SnO2 and PbS–SnO2 nanocomposites. The thermal behavior, magnetic, photocatalytic and antifungal properties of the synthesized samples were investigated. The composite becomes well crystallized above 284 °C. Diffraction peaks related to PbS and SnO2 were observed in the XRD pattern of the composite. EDX spectrum confirms the presence of the elements Pb, S, Sn and O in the composite. Functional groups related to Pb–S and Sn–O is evinced from the FTIR spectrum. Photoluminescence studies confirm that the PbS–SnO2 nanocomposite has optical band gap value intermediate between pure PbS and SnO2 nanopowders. Photocatalytic studies confirm that the PbS–SnO2 composite have better degradation efficiency against methyl orange compared to that of pure PbS and SnO2 nanopowders. Enhanced ferromagnetic behavior is observed for the composite. The composite had better antifungal efficiency against A. niger fungus strain.

Synthesis of Nanostructured Tin Oxide by Sol–Gel and Sonochemical Approaches in an Ionic Liquid

Abstract The present paper shows a comparative study on the synthesis of nanostructured tin oxide in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO) by sol–gel and sonochemical methods. The XRD results of the synthesized materials revealed the formation of single tetragonal phase of SnO2 by sol–gel method whereas a mixture of tetragonal SnO and orthorhombic SnO2 phases was obtained by the sonochemical method. The sonochemical approach led to the formation of finer nanoparticales with a higher specific surface area than that of the sol–gel synthesized oxide. The average sizes of tin oxide nanoparticles were found to be about 30 nm and 15 nm for the particles obtained by sol–gel and sonochemical methods, respectively. The surface area of SnO2 nanopowder obtained by the sol–gel method (calcined at 500 °C) was estimated to be 11.6 m2 g−1, and the mean pore diameter was found to be 6.33 nm. Whereas the mixed SnO/SnO2 sample (calcined at 500 °C) obtained by the sonochemical method exhibited a higher surface area of 43.11 m2 g−1 and an average pore diameter of 1.90 nm. The band gap of the synthesized tin oxides was estimated from the UV-vis. results to be 4.01 and 4.25 eV for the sol–gel and sonochemically synthesized samples, respectively.

Phase transformation and chemical decomposition of nanocrystalline SnO2 under heavy ion irradiation

A crystalline-to-crystalline phase transformation, including chemical decomposition, has been observed in SnO2 nanopowder irradiated by 2.2GeV 197Au ions. X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM) were used to characterize the transformation from tetragonal SnO2 (P42/mnm) to tetragonal SnO (P4/nmm), with trace quantities of β-Sn (I41/amd). At a fluence of approximately 2.0×1012ions/cm2, diffraction maxima corresponding to SnO became clearly evident and increased in intensity as fluence increased. The proportion of SnO, as determined by Rietveld refinement of XRD data, reached 23.1±0.8% at the maximum fluence investigated of 2.4×1013ions/cm2. Raman spectra show high photoluminescence (PL) intensity before and during initial SnO formation, indicating the importance of oxygen vacancies in the transformation process. Small-angle X-ray scattering (SAXS) analysis provided evidence of ion tracks, but no tracks were observed using high-resolution TEM (HRTEM). The transformation likely occurs through a multiple-impact mechanism, based on the accumulation of O vacancies, defect ordering, and partially localized Sn reduction.

Magnetic and antibacterial properties of Zr-doped SnO2 nanopowders

Zirconium doped tin oxide (SnO2:Zr) nanopowders were synthesized by a simple soft chemical route adding various concentrations of zirconyl chloride (0, 5, 10 and 15 wt%). The samples were characterized by techniques like XRD, SEM, TEM, EDX, FTIR spectroscopy, UV–Vis-NIR spectroscopy and photoluminescence spectroscopy. XRD studies confirm that all the samples exhibit rutile tetragonal crystal structure with a strong (1 0 1) preferential growth texture. Hexagonal shaped grains were evinced from the SEM images. Nanosized grains are evinced from the TEM images and EDX spectra confirm the presence of Zr in the doped samples. The bands at 523 and 583 cm−1 observed in the FTIR spectra which are attributed as the characteristics of γ (Sn–OH) terminal bond of the SnO2 crystalline phase confirm the presence of Sn–O in the synthesized samples. The doped samples exhibit ferromagnetic behavior. Enhanced antibacterial activity was observed for the doped samples. The obtained results show that zirconium strongly influenced the structural, morphological, optical, magnetic and antibacterial properties of pure SnO2 nanopowders.

Photocatalytic activity of different organic dyes by using pure and Fe doped SnO2 nanopowders catalyst under UV light irradiation

A facile, chemical precipitation method has afforded highly crystalline iron (Fe) doped SnO2 nanoparticles with efficient photocatalytic degradation of phenol and benzoic acid under ultraviolet light irradiation. Powder X-ray diffraction results show that the both pure and Fe doped SnO2 samples are in tetragonal rutile type SnO2 phase and the results are well matched with the standard data (card no. 41-1445). Transmission electron microscope reveals that the morphology of the samples was spherical in shape and the average particle sizes were around 24–42 nm, which is in good agreement with the XRD results. UV–VIS transmission spectroscopy studies show that the band gap energy of pure SnO2 is 3.63, and 3.53, 3.34 eV for Fe-doped (3 & 5 wt%) SnO2 nanoparticles respectively. Energy dispersive spectra (EDS) spectra confirm the presence of Fe in the most active Fe-modified SnO2 sample. Fe-doped SnO2 sample exhibited enhanced activity for both phenol and benzoic acid under ultraviolet irradiation, which could be due to the Eg decreased by Fe-doping, high specific surface area and porous structure. The samples were further characterized by Fourier transform infrared (FTIR) and photoluminescence spectra analysis. The photocatalytic mechanism of Fe doped SnO2 also discussed.

Enhanced antibacterial and photocatalytic activity of (Mg+Co) doped tin oxide nanopowders synthesised using wet chemical route

In this study, the photocatalytic activity of pristine and (Mg+Co) doped tin oxide (SnO2) nanopowders have been investigated towards the degradation of aqueous solutions of Methylene Blue (MB) and Malachite Green (MG). In addition, the antibacterial activities of the synthesised samples were evaluated against Gram-positive Staphylococus aureus bacteria and Gram-negative Pseudomonas aeruginosa bacteria by the well diffusion method. The SnO2: Mg: Co nanopowders exhibit superior photocatalytic activity when compared with pristine SnO2. The degradation process follows a pseudo-first-order kinetics. The rate constant of SnO2: Mg: Co nanopowder is 1·2 times greater than that of pristine SnO2 nanopowder for the degradation of MB dye while for MG dye degradation, it is 1·5 times. Moreover, antibacterial activity of SnO2: Mg: Co nanopowder showed better antibacterial properties compared to pristine SnO2. The above mentioned samples were synthesised using a simple and low-cost soft chemical process.

Evaluating the Potential Benefits of Metal Ion Doping in SnO2 Negative Electrodes for Lithium Ion Batteries

Nine different transition metal doped (<10 at%) tin dioxides and undoped SnO2 nanopowders with similar specific surface areas were made using a continuous hydrothermal process and then investigated as potential negative electrode materials for lithium ion batteries. The as-prepared nanopowders were characterized via a range of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectroscopy, X-ray fluorescence spectrometry, transmission electron microscopy, thermogravimetric analysis and Brunauer-Emmett-Teller surface area measurements. Doped SnO2 materials were grouped into two classes according to the potential redox activity of the dopant (those presumed to be redox inactive: Nb, Ti, Zr; and those presumed to be redox active: Fe, Co, Cu, Zn, Mn, Ni). The role of the transition metal ion dopant on the cycling performance (overall capacity and voltage hysteresis), was elucidated for the first cycle via cyclic voltammetry measurements in half cells versus lithium metal. In particular, the authors were able to evaluate whether the initial Coulombic efficiency and the delithiation potential (vs. Li/Li+) of the doped samples, would be likely to offer any increased energy density (compared to undoped SnO2) for lithium ion batteries.

Low-Working-Temperature and High-NO&lt;sub&gt;2&lt;/sub&gt;-Sensing Properties of SnO&lt;sub&gt;2&lt;/sub&gt;/PANI Hybrid Material Sensors

In this work, SnO2 porous nanosolids were obtained from SnO2 nanopowders by using a solvo-thermal hot-press method. Then, by using the conventional thick-film sensors preparation technology, SnO2 porous thick-film gas sensor was prepared from it. Meanwhile, polyaniline (PANI) was synthesized by chemical oxidation polymerization. After that, by mechanical method, the SnO2/PANI composite gas sensors were fabricated. The intrinsic resistances and gas sensing properties of sensors to NO2, NH3, H2 and ethanol vapor were tested. Compared with the SnO2 porous gas sensors, the optimum operation temperature of SnO2/PANI hybrid gas sensors decreased dramatically. And SnO2/PANI hybrid gas sensors showed satisfying selectivity and high sensitivity for NO2.

Synthesis of SnO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Nanopowders for Advanced Ceramics and Electronic Sensor Transducer Devices and Characterization and Band Gap

Reverse Microemulsion Precipitation” was firstly developed for synthesizing SnO2 nanopowders were intended to as advanced structural materials and hazardous gases, particulates (Pb, Cd, Hg) sensing nanofabricated devices: sensor, transducer, MOSFET, electrodes. Prepared controlled nanopowders were encapsulated with oil phases in spherical water pole at water to surfactant mole ratio w0=8 and w0=10. Characteristic absorption of semiconductor at 303.4 nm and no absorption in higher  and absorption edge in the 321.6-371.6 nm and band gap energy (3.6eV) were observed by UV-Vis measurement confirmed 2SnO2.4H2O nanoparticles is semiconductor. Sn-O stretching band at 678.94 cm-1 and no other groups presence confirmed complete removal of adsorbed chemicals in the course of calcination at 600°C about 4.0 hours from FTIR spectrum. XRD investigation found out phase pure tetragonal SnO2 nanocrystalline structures and average crystalline size 0.2380 nm at w0=8. SEM images exhibited spherical morphology counting average particle size 153.242 nm and 131.604 nm and average diameter 8.02 nm at w0=8 and 10.01 nm at w0=10 respectively. Higher specific surface area was observed 107.731 m2/ g (count 637) more than 86.314 m2/ g (count 341) of relatively larger diameter which is more pronounced compared to ordinary Reverse Microemulsion Method. Findings and standards established this synthesis method as suitable for obtaining the higher degree of surface area and finest crystallinity.

A facile and one step synthesis of W doped SnO2 nanopowders with enhanced humidity sensing performance

High sensitivity and fast response humidity sensor based W doped SnO2 nanopowders were prepared by hydrothermal method. The structural, morphological and optical properties of the films nanopowders were analysed by using powder X-ray diffraction (XRD), Transmission electron microscope (TEM), UV–Vis transmission spectra, Fourier transform infra-red spectra and photoluminescence spectra analysis. XRD results suggest that both pure and W doped samples had a tetragonal rutile type structure and the results are in good agreement with the standard JCPDS data (card no# 41-1445). The uniform distribution and well crystalline elongated spherical shaped rod like morphology was observed by TEM micrographs. UV and PL results confirmed the optical property of pristine SnO2 was significantly improved by W doping. Humidity sensor set up was fabricated and tested for relative humidity (RH) variation from 10 to 90%. The 10 wt% doped W sample showed high sensitivity fast response and recovery time as compared to other samples. The humidity sensing results showed that W–SnO2 can be used as active nanostructures for humidity sensors. The humidity sensing mechanism was also discussed in detail.

Porous LaFeO3/SnO2 nanocomposite film for CO2 detection with high sensitivity

Perovskite LaFeO3 nanocrystalline powder, synthesized by sol–gel method, was composited with SnO2 nanopowders to fabricate porous LaFeO3/SnO2 thick film sensors. The as-prepared sensors exhibit high gas sensitivity, fast response and low working temperature for CO2 detection. The optimal sensing performance of LaFeO3/SnO2 thick film sensors is obtained with the molar ratio of La/Sn = 1:1. The observed response is nearly 2 times higher than that of bare LaFeO3 at 4000 ppm CO2 and the response time is less than 20 s at 250 °C. CO2 sensing mechanism of the as-prepared nanocomposites porous film is addressed. The results demonstrate that the as-formed P-N junctions can greatly enhance the carrier transfer efficiency which is attributed to the improved sensing performance. Moreover, the hydroxyl species absorbed on the surface of the nanocomposites are also involved in the sensing process.

Synthesis and photoluminescent properties of Sm3+-doped SnO2 nanoparticles

SnO2 ceramic nanoparticles homogeneously doped with Sm3+ ions were synthesized via a sol-gel method, followed by drying and annealing in air. X-ray diffractometry, FT-IR spectrometry and transmission electron microscopy were used to characterize the nanoparticulate samples. After annealing, both doped and undoped SnO2 nanopowders were shown to adopt the rutile tetragonal crystal form and to exhibit characteristic Sn–O–Sn vibrations. The average particle size was found to be in the region of 23–28nm. Photoluminescence analysis at room temperature demonstrated strong enhancement of the visible emission from Sm3+, via energy transfer from the SnO2 host matrix to the dopant. The maximum emission efficiency was observed for a concentration of 1.5 atom% Sm3+.