Ag-doped SnO2 Research Articles

Biosynthesis of the Ag Doped SnO2 Nanorods Supported Bentonite Clay with Enhanced Photocatalytic Activity Against Crystal Violet Dye

Biosynthesis of the Ag Doped SnO2 Nanorods Supported Bentonite Clay with Enhanced Photocatalytic Activity Against Crystal Violet Dye

Synthesis of Ag-doped SnO2 nanoflowers and applications to room temperature high-performance NO2 gas sensing

SnO2 has attracted much attention in the field of gas sensors due to its unique structure and properties. In this work, SnO2 nanoflowers doped by Ag structures were prepared by a facile hydrothermal synthesis method. Ag doping not only increases the number of oxygen vacancies in the composite, but also alters the carrier migration behavior and significantly increases the carrier concentration, promoting the electron transport rate. Additionally, Ag doping enhanced the conductivity and catalytic activity of the composite, making it highly selective for NO2. At room temperature (RT), Ag-doped SnO2 sensor exhibit excellent gas-sensitizing properties. At the NO2 concentration of 100 ppm at RT (25 °C, 25 % RH) the prepared 2 at% Ag-SnO2 sensor has a response value of 73.0 (Ra/Rg), a response time of 1.4 s, and a detection limit as low as 10 ppb. Its long-term stability is up to 90 days. Doping is an effective way to improve gas sensing performance. It solves the disadvantages of low sensitivity and poor selectivity of SnO2.

Ginger (Zingiber officinale)-Mediated Green Synthesis of Silver-Doped Tin Oxide Nanoparticles and Evaluation of Its Antimicrobial Activity.

Green synthesis of nanoparticles using plant extract is a novel development that has gained significant attention because of its low cost, nontoxicity, and environmental friendliness. In the present study, silver-doped stannic oxide (Ag-doped SnO2) nanoparticle was synthesized by an eco-friendly green synthesis method. The synthesized samples were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and their antimicrobial activities were assessed against two bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aurus) and two fungi Fusarium oxysporum (F. oxysporum) and Fusarium graminearum (F. graminearum) by using the disk diffusion method. Ag-doped SnO2 nanoparticles show a strong and broad absorption from UV-vis spectra when compared to pure SnO2 nanoparticles. FTIR spectral analysis revealed that the peak at 505.69 cm-1 was assigned to Sn-O and O-Sn-O stretching vibration of SnO2 nanoparticles. XRD analysis confirmed the formation of a tetragonal rutile structure with average particle size ranging from 10 to 17 nm. The antimicrobial result indicates that the Ag-doped SnO2 revealed significant antimicrobial activity against both bacterial and fungi strains with the zone of inhibition of 29 ± 0.54, 27 ± 0.05, 17 ± 0.05, and 15 ± 0.05 mm for S. aureus, E. coli, F. oxysporum , and F. graminearum, respectively. Thus, the studies suggested that Ag-doped SnO2 nanoparticles exhibit good activity against both Gram-negative and Gram-positive bacteria and fungi. This is because doping SnO2 nanoparticles with metallic elements such as Ag has been used to enhance their performance, confirming them as a good candidate for antimicrobial agents and the development of future therapeutic agents.

Ternary photocatalyst of Fe3O4/Ag-SnO2 with Parkia speciosa extract improves visible-light-driven photocatalytic degradation of dye

SnO2 is a highly utilized and cost-effective photocatalyst in various industries, including industrial polishes, glass and ceramic coatings, building materials, and gas sensor systems. However, the light emission process has limitations due to the rapid recombination of electrons and holes. In order to overcome this issue, an innovative study was conducted in which a cheap and non-toxic plant extract precursor with phytochemicals was used as a capping agent. Fe3O4/Ag-dopedSnO2 nanocomposites with varied Ag and SnCl2 ratios were synthesized, and the samples were characterized using FTIR, UV–visible, XRD, SEM, TEM, XPS, and BET surface analyses. Adding Ag to the nanocomposites slowed down the recombination of charge carriers. This made Fe3O4/Agx-SnyO2 (x:y = 1:1, 1:3, 3:1) a better photocatalyst than Fe3O4 or SnO2 alone. Rhodamine B, a model pollution dye, was decomposed under 50 W LED light to test the efficiency of the as-synthesized nanocomposite photodecomposition. When illuminated with LED light, the Fe3O4/Agx-SnyO2 (FAS3) (x:y=3:1) nanocomposite displayed increased photocatalytic activity. These results showed that excited charge electrons from SnO2 could move to the Ag conductive band to speed up charge pair separation. This would make the photocatalysis of Ag-doped SnO2 more effective at breaking down dye.

Room temperature solid electrolyte ozone sensor based on Ag-doped SnO2

In this paper, SnO2 was synthesized using MOFs as a sacrificial template, and Ag-doped SnO2 composite was synthesized by reducing AgNO3 with NaBH4, and O3 sensors were prepared using sodium superionic conductor (NASICON) as a solid electrolyte. At room temperature, the gas-sensitive experimental tests showed that the response of the sensor with 3 wt% Ag-SnO2 to 180–420 ppb O3 increased by about 57% and the sensitivity increased by 9.9% compared to the pure SnO2 sensor. The repeatability and stability of the 3 wt% Ag-SnO2 sensor were tested at 240 ppb O3, and the results showed that the repeatability of the sensor varied between − 2% and 2%, and the stability varied between − 4% and 4%. Therefore, the solid electrolyte sensor prepared by the excellent Ag-doped SnO2 composite material has a good application prospect in the detection of low-concentration O3.

One-step hydrothermal synthesis of uniform Ag-doped SnO2 nanoparticles for highly sensitive ethanol sensing

One-step hydrothermal synthesis of uniform Ag-doped SnO2 nanoparticles for highly sensitive ethanol sensing

Effect of Ag doping on structural, optical, complex impedance and photovoltaic properties of SnO2 nanoparticles prepared by co-precipitation method for dye sensitized solar cell application

The pure SnO2 and Ag-doped snO2 nanoparticles (NPs) were prepared by co-precipitation method. The structural, electrical and optical properties of the material were systematically studied. The XRD patterns of both samples reveal that the presence of cassiterite tetragonal structure and GSAS fittings confirms the incorporation of Ag in SnO2 lattices. The SEM-EDS analysis reveals that the presence of spherical-shaped NPs with the expected elements. The Raman spectra of Ag-doped SnO2 NPs show that the two extra local disorder vibrational modes while comparing with pure SnO2. The UV-Vis spectroscopy result shows that the Ag doping reduces the optical band gap and increases Urbach tail energy with a reduced effective energy band gap in Ag-doped SnO2 NPs. The Photoluminescence spectrum confirms the presence of the defects like oxygen vacancies; however, these defects are increased by the Ag-doped SnO2 system. From the dielectric measurements, the conductivity of both samples followed Jonscher’s power law. The nonlinear least-square fittings on Nyquist plots of both samples suggested that the conduction process took place predominantly through grain boundary in SnO2 NPs whereas through grains in Ag-SnO2 NPs. This nature of band gap narrowing with increased conductivity in Ag-doped samples drives these samples for good solar cell activity applications. As expected, photovoltaic measurements show higher power conversion efficiency in Ag-doped SnO2 NPs. These results were discussed by correlating optical and dielectric properties of SnO2 and Ag-doped SnO2 NPs which gave a broad understanding for device fabrications successfully.

Enhanced Methane Sensing Properties of SnO2 Nanoflowers With Ag Doping: A Combined Experimental and First-Principle Study

Ag-doped SnO2 nanoflowers (NFs) are prepared via a simple one-step hydrothermal method and subsequent Ag-doping using AgNO3 solution as precursors. The crystal structure, morphology and elements of the Ag-doped SnO2 NFs are investigated in detail. The maximal response of Ag-doped SnO2 sensor with 1.0 wt.% Ag doping to 500 ppm methane is increased by a factor of 1.6 as compared to that of pure SnO2 sensor. The long-term stability and the selectivity of the SnO2-based sensor are improved by Ag-doping as well. Meanwhile, pre-adsorption of oxygen molecules on the surface of the SnO2-based substrate is studied in-depth with the method of first-principle calculation. Ag doping lowers adsorption energy for all the adsorption sites, demonstrating a higher adsorption stability of chemisorbed oxygen ions on the Ag-doped SnO2 as compared to the pristine phase. More electron transfer from the semiconductor to the chemisorbed oxygen is revealed by the Mulliken charge analysis and the electron density difference for the Ag-doped SnO2, explaining the better sensitivity of gas sensors based on Ag-doped SnO2 nanostructures as compared to its undoped counterpart.

On the modeling of the multi-segment capacitance: a fractional-order model and Ag-doped SnO2 electrode fabrication

On the modeling of the multi-segment capacitance: a fractional-order model and Ag-doped SnO2 electrode fabrication

Effect of Ag doping on SnO2 sensing for detecting H2S: A first-principles study

First-principles calculations were performed to investigate the effect of Ag doping on SnO2 sensing of H2S with oxygen vacancy formation and oxygen species preadsorption. Ag preferentially substituted for Sn5c atoms, and Ag atoms were favorable for the generation of oxygen vacancies at O2c sites on the SnO2 (110) surface. The adsorbed O2 molecules dissociated on the Ag-doped SnO2 surface more easily because of the dopant catalysis, and the resistance of the Oads-preadsorbed Ag-doped SnO2 surface increased because of increased electron transfer from the surface to the Oads species. When exposed to H2S, H2S released more electrons back to the Oads-preadsorbed Ag-doped SnO2 surface, thereby increasing surface conductance. Therefore, Ag doping enhanced SnO2-semiconductors sensing. This study can provide an improved understanding of Ag-enhanced SnO2 sensing, which is helpful for designing SnO2 sensors with high sensitivity and sensing response.

Anti- blight effect of green synthesized pure and Ag-doped tin oxide nanoparticles from Averrhoa bilimbi fruit extract towards Xanthomonas oryzae-the leaf blight pathogen of rice

Green synthesis of nanoparticles using plant extract is a novel substitute for conventional chemical or physical methods. A simple green synthesis of pure and Ag-doped tin oxide nanoparticles from the fruit extract of Averrhoa bilimbi and their antibacterial activities have been demonstrated in this work. Silver has been doped into tin oxide for a perceived enhanced antibacterial activity. Techniques like UV-DRS, XRD, FTIR, and TEM were used to characterize the green synthesized nanoparticles. An average crystalline particle size of 2.6 nm was observed in XRD studies. Apart from the structural elucidation, the zeta potential values of the particles were also done. The antibacterial activity of pure and doped nanoparticles against the bacterial leaf blight pathogen, Xanthomonas oryzae was tested adopting standard assays employed in antimicrobial analysis. A significant advantage of using the biosynthesized SnO2 and its silver-doped variant was noticed in all the assays carried out. The impact of nanoparticle in the cellular protein leakage and the stress-induced enzyme release was carried out using Bradford’s method and DPPH assay respectively. Based on the biofilm inhibition studies, the inhibitory effect of the nanoparticles towards xanthomonadin and exopolysaccharide formation was reaffirmed. The DNA cleavage analysis carried out also was found to be a proof of the bactericidal effect of the nanoparticles. Overall results point to a promising use of Ag-doped SnO2 nanoparticles against the leaf blight disease caused by Xanthomonas oryzae in rice.

Metal organic frameworks derived SnO2 microsphere doped Ag for monitoring low concentration ethanol

Pyrolyze metal-organic frameworks (MOFs) is a promising method to prepare metal oxides with large specific surface and multiple active sites. The obtained metal oxides can be utilized as gas sensors. Noble metal doping is an effective way to improve the gas sensitivity of materials. In this work, SnO2 are prepared by pyrolyzation of metal organic frameworks and Ag-doped SnO2 composites are fabricated by AgNO3 reduction in a water bath at 4 °C. The gas-sensing experiment reveals that the optimum operating temperature of different mass fraction of Ag doped SnO2 samples is 250 °C which is lower than pure SnO2 (300 °C). The response of composites (7 wt% Ag–SnO2) is 157 to 10 ppm ethanol, which is about 10 times higher than pure SnO2 (14). The composites have good selectivity and stability. Such excellent performance is contributed to the increase of the gas adsorption capacity, catalytic active site and oxygen vacancy of the composites caused by the doping of Ag.

Room temperature d0 ferromagnetism, zero dielectric loss and ac-conductivity enhancement in p-type Ag-doped SnO2 compounds

d0 Ferromagnetic oxide materials have emerged as a promising material for possible application in spintronics. The recent theoretical calculation has predicted d0 ferromagnetism in Ag-doped SnO2 compounds. In this work, we have undertaken an investigation into structural, micro-structural, optical, magnetic, and electrical properties of Ag doped SnO2 compounds. Crystal structure study by the XRD pattern analysis confirms polycrystalline rutile phase with tetragonal structure. The SEM micrographs reveal the formation of uniform spherical nanoparticle morphology. The optical property study by UV/VIS spectrophotometer indicates the band-gap narrowing. A p-type conductivity was observed by Hall effect measurement and the hole concentration was found to increase with the increase in Ag doping. Ferromagnetism with Curie temperature ranging from 304 to 359 K is observed in all Ag-doped compounds, along-with a coercivity value of 240–1310 Oe, whereas un-doped SnO2 exhibited diamagnetism. The magnitude of dielectric constant and ac conductivity was observed to enhance with an increase in Ag concentration, which implies that the charge carriers' hopping is responsible for this transport. The observed ferromagnetism can be ascribed to a p–d hybridization between O and Ag ions.

SEM-Net: Deep features selections with Binary Particle Swarm Optimization Method for classification of scanning electron microscope images

Materials Science is increasingly handling artificial intelligence methods to address the complexity in the field of everyday life necessities. Researchers in both academia and industry are interested in imaging techniques used in the characterization of nanomaterial with designed properties to meet the needs of applications in the literature. However, the increase in image size and complexity in its content restricts the use of traditional methods. Recent advances in machine learning have been used to benefit computers' potential to make sense of these images. The approach proposed in this paper aims for the feature reduction with the Binary Particle Swarm Optimization method to execute the classification process on SEM images by concatenating the deeper layers of pre-trained CNN models AlexNet and ResNet-50. The feature vectors were used as input to support vector machine classifier (SVMC) after dimension reduction to obtain the final model. Finally, the trained model's performance was tested using SEM images of Ag-doped SnO2 nanoparticles, which were prepared by the author using the low-temperature hydrothermal method. To the best of the author knowledge, these images were not available in the databases. The best accuracy value was observed with 3112 features for the SEM dataset with optimized vectors as 99.3 %. An example was illustrated where the feature selection with the BPSO technique could provide novel insight into nanoscience research and test the model with the SEM images of Ag-doped SnO2 particles that are obtained by the hydrothermal method.

Enhancing room temperature ethanol sensing using electrospun Ag-doped SnO2–ZnO nanofibers

The present study reports room temperature ethanol sensing with improvement in response and recovery times using Ag-doped SnO2–ZnO composite nanofibers. A comparative study of nanofibers of solo SnO2, SnO2–ZnO nanocomposite and Ag-doped SnO2–ZnO nanocomposite is presented. Nanofibers of tin oxide and zinc oxide are deposited on low-cost aluminum electrodes using electrospinning technique to analyze their gas sensing characteristics towards volatile organic compounds, especially ethanol. The effect of Ag doping on nanocomposite of SnO2 and ZnO has been studied and analyzed in terms of various gas sensing parameters viz. % response, response/recovery time, and selectivity. Ag-doped SnO2–ZnO nanofibers have shown excellent response towards low concentration of ethanol (38.78% for 0.5 ppm) at room temperature (RT) with quick response and recovery times. X-ray diffraction, X-ray photoelectron spectroscopy, I–V characterization, energy dispersive X-ray spectroscopy, and scanning electron microscopy characterizations are done to show the crystallite size, valence state, electrical properties, elemental analysis, and surface morphology of the deposited nanofibers, respectively. The effect of doping on the surface characteristics is also analyzed by calculating and comparing the crystallite size of doped and undoped nanofibers. Moreover, the use of sol–gel process route, electrospinning deposition technique, and aluminum as the electrode and glass substrate make the fabrication of the sensor very cost effective.

Electrospun Ag-Doped SnO2 Hollow Nanofibers with High Antibacterial Activity

With the continuous improvement in medical science in modern times, the spread of bacterial infection has become a matter of global concern. Therefore, the search for biological medical materials with antibacterial function has become a focus of intense research. In this work, pure SnO2 and Ag-doped SnO2 hollow nanofibers were fabricated by a combination of an electrospinning method and a calcination procedure, and the effects of the doped Ag on antibacterial activity and catalytic antibacterial activity were subsequently investigated. Through the process of high-temperature calcination, a high heating rate would lead to the formation of a hollow tubular structure in SnO2 fibers, and Ag2O would be reduced to Ag0 by a facile process with appropriate thermal treatment. Additionally, the existence of SnO2 as a tetragonal rutile structure was confirmed. On the basis of pure SnO2, doping with Ag greatly improved the antibacterial activity and catalytic antibacterial activity of hollow nanofibers. The formation mechanism and the antibacterial mechanism of pure SnO2 and Ag-doped hollow nanofibers are also discussed. This study has broad application prospects for biological medicine.

Inclusion of cobalt reinforced Ag doped SnO2 properties: electrical, dielectric constant, magnetic and photocatalytic insights

Cobalt as a second dopant played remarkable roles in enhancing the electrical conductivity, dielectric constant, ferromagnetic and photocatalytic properties of Ag doped SnO2 nanoparticles. Pure, Ag doped and Ag/Co codoped SnO2 nanoparticles were synthesized by co-precipitation method. Rietveld refinement analysis for XRD data confirmed the single phase nature in all SnO2 compositions with tetragonal rutile structure. The noticeable changes in the unit cell volume of SnO2 established for the successful incorporation of Ag and Co ions into its host lattice. SEM and TEM images clearly showed the formation of very fine spherical nanoparticles with uniform distribution. The binary dopants of Ag/Co ions induced blue shifts in SnO2 band gap due to Burstein-Moss effect. Notable increases in the electrical conductivity of (Ag, Co) codoped SnO2 samples compared to pure one were detected. The adsorption and desorption of the oxygen species on SnO2 surface have showed significant influences on the conductivity-temperature behavior. The dielectric constant as function of frequency was discussed based on the Maxwell–Wagner model. Sn0.97Ag0.01Co0.02O2 structure exhibited the highest dielectric constant of 3129 at low frequency (42 Hz). Also, insertion of Co plus Ag ions stimulated perfect ferromagnetic loops and enriched the magnetic parameters of SnO2. The enhanced ferromagnetism was discussed based on F-center exchange interaction between Co2+ ions via oxygen vacancies (↑Co2+–↓Vo–↑Co2+). Besides that, the load of Co ions made a high jump in the photocatalytic activity of Ag doped SnO2. High activity, 97%, for methylene blue (MB) degradation was realized through Sn0.95Ag0.01Co0.04O2 catalyst with practical efficiency stability for three cycles within 97–88%. Cobalt played a main role in the separation of the photogenerated electron–hole pairs plus oxygen vacancies formation which improved the photocatalytic activity.

Investigation of Ag-Doping in Kinetically Sprayed SnO2 Composite Film and Its Application to Gas Sensor

We have developed a facile method to fabricate Ag-doped SnO2 composite film prepared via one-step kinetic spraying process. We used supersonic/subsonic nozzles to accelerate powders to their maximum kinetic energies when bombarding the substrates; no post-treatment was required. Under optimized conditions, sensors fabricated from SnO2-based films with and without Ag nanoparticles (NPs) were smooth and about 7 µm in thickness. To improve CO-sensing performance, Ag NPs (to less than 1 wt%) were added to SnO2 films. The sensor response to CO of the film with 1 wt% Ag was up to 20-fold better than that of the Ag-free film, even a low CO concentration of 500 ppm. We thus confirmed that addition of a small amount of Ag NPs to a SnO2 film increased electron transport and improved catalysis of oxygen ionization on the film surface. Therefore, we have developed a facile method of Ag-doping in composite gas sensor and this crack-free composite gas sensor was found to be highly sensitive to CO gas.

Microwave Assisted Synthesis of Pure and Ag Doped SnO2 Quantum Dots as Novel Platform for High Photocatalytic Activity Performance

In this study, we report a simple and fast synthetic route to prepare pure and Ag doped SnO2 quantum dots via one step microwave irradiation method for the first time. Variety of analytical techniques including XRD, Raman, TEM, EDS, XPS, UV and PL were used to investigate the influence of Ag dopant concentration on structural, morphological, compositional and optical properties of SnO2 nanoparticles. The XRD pattern showed a dominant tetragonal rutile structure of both pure and Ag doped SnO2 and formed directly during the microwave irradiation process. TEM images revealed that quantum dots and the average particle size increases by Ag doping. The EDS and XPS results proved that the presence of silver as Ag3+ species. The optical properly of SnO2 was significantly improved and narrowing the band gap (3.54–3.09 eV) of pure SnO2 by Ag doping, which is confirmed through UV and PL results. The photocatalytic behavior of the catalyst powders were investigated using methylene blue and rhodamine B (RhB) as model organic pollutants. A maximum RhB degradation efficiency of 97.5% is achieved under visible light irradiation for Ag doped SnO2 catalyst. Furthermore, the Ag–SnO2 QDs catalyst demonstrates good reusability and stability after the seven cycles.

Characterization of Ag Doped SnO2 for Gas Sensing Application

We used Transmission Electron Microscopy TEM, Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD) and impedance spectroscopy to study SnO 2 doped by sputtered Ag atoms on its surface. The morphology of the surface texture showed large Ag islands in SnO 2 bulk when the system was submitted to heating. These results were well confirmed by EDX spectrum, TEM scanning micrograph and impedance spectroscopy. Furthermore, TRIM software was used to show the effects of nuclear and electron stopping range on optical properties of the crystal Ag-SnO 2 and the depth reached by Ag into SnO 2 bulk.