Flower-like SnO2 Nanostructures Research Articles

Template preparation of porous Pt-modified SnO2 microflowers for high-response detection of VOCs

Porous SnO2 microflowers consisting of uniform nanosheets modified by Pt nanoparticles were synthesized using a self-sacrificing template followed by a reduction strategy. The Pt@SnO2, SnO2–Se, and SnO2–S samples were characterized using a series of techniques. The gas-sensing behaviors of the samples toward volatile organic compounds (VOCs) were studied. The Pt@SnO2 sensors exhibited superior gas-sensing performance for formaldehyde gas. The Pt@SnO2 sensors presented a stronger response (100.2), shorter response–recovery times (14 s/23 s), and lower working temperature (200 °C) for 100 ppm formaldehyde gas. The Pt@SnO2 sensors also showed excellent responses toward other VOCs, such as 100 ppm ethanol (82.5), acetone (73.9), and isopropanol (62.1). The gas-sensing mechanism of the Pt@SnO2 sensors was examined. The larger available surface area, favorable hierarchical flower-like nanostructure assembled by nanosheets, larger pore size, and larger proportion of oxygen vacancies and adsorption-state oxygen species, smaller crystallite size, and spillover effect of Pt catalysts contributed to the enhanced gas-sensing behaviors of Pt@SnO2 sensors. Overall, the synthetic strategy for flower-like SnO2 nanostructures can be applied widely.

Highly Sensitive Isopropanol Gas Sensor based on SnO2 Nano-Flowers on Gold, Silver, and Aluminum Interdigitated Electrodes

In this research we have proposed a high selectivity Isopropanol gas sensor. The sensor shows significant resistance change only to Isopropanol gas. The synthesis method of flower-like SnO2 nanostructures, the electrode material and design, and the optimized working temperature provide the high selectivity and high response of the sensor. The SnO2 nanoflowers (NFs) have been synthesized in a two-step process as the gas sensitive layer. The sensor shows its best performance on Au interdigitated electrodes. The optimized working temperature is obtained at 150 °C. The proposed sensor has a high sensitivity, good repeatability, long-term stability and remarkable selectivity. The responses of the sensor to 100 ppm of isopropanol at 150 °C is 71 and the sensor is capable of keeping almost 96% of the initial response in a 40 d period.

Pr doped SnO2 nanostructures: Morphology evolution, efficient photocatalysts and fluorescent sensors for the detection of Cd2+ ions in water

We report the effect of Pr doping on structural, morphological, optical, photocatalytic properties and heavy-metal ion sensing behavior of 3D flower-like SnO2 nanostructures synthesized using hydrothermal method by varying Pr concentration from 0 to 10 mol%. The synthesized samples have been characterized by various analytical techniques. The results indicate that the morphology of SnO2 nanostructures can be tailored by changing the Pr-dopant concentration in a reasonable range. Crystallographic studies reveal the lattice distortion with an increase in Pr doping concentration in SnO2 host lattice. Moreover, the photocatalytic activity of SnO2 studied by the degradation of Rhodamine-B (RhB) dye in aqueous media shows excellent performance on 10 mol% praseodymium doping, which may be attributed to its specific morphology, smaller size and larger surface area as seen from BET measurements. Further, the sensors based on 10 mol% Pr-doped SnO2 nanostructures shows highest fluorescence quenching efficiency (0.22) as compared to pure SnO2 and other doped samples at lowest concentration of Cd2+ (0.01 μg/ml) in drinking water with Limit of Detection (LOD) as low as 0.008 μg/ml. The possible formation mechanism of Pr-doped SnO2 nanostructures and the heavy metal-ion sensing mechanism of sensors has been proposed and discussed in detail.

Enhanced photovoltaic performance of dye sensitized solar cell using SnO2 nanoflowers

The study highlighted enhanced performance of SnO2 based DSSC using photoanode with nanostructured morphology. The simple organic surfactant free hydrothermal synthesis method was used for preparation of SnO2 nanoflowers for dye sensitized solar cell (DSSC) application. The hydrothermal reaction time was varied to obtain different SnO2 nanostructures. The hydrothermal reaction time showed considerable effect on optical and structural properties of the prepared samples. The results indicated that the prepared samples were pure rutile SnO2. The band gap of prepared samples was greater than bulk SnO2 and varied from 3.64 to 3.81 eV with increase in hydrothermal reaction time. With increase in reaction time from 4 to 24 h, the microstructure of SnO2 changed from agglomerated nanoparticles to nanopetals and finally to self-assembled nanoflowers. Flower-like SnO2 nanostructures showed size around 300–700 nm, and composed of large numbers of 3 dimensional petals connected with each other forming 3D nanoflowers by self-assembly. Consequently, the DSSC with flower-like SnO2 nanostructures exhibited good photovoltaic performance with Voc, Jsc and η about 0.43 V, 4.36 mA/cm2 and 1.11%, respectively.

One-step synthesis of novel hierarchical flower-like SnO2 nanostructures with enhanced photocatalytic activity

Novel hierarchical flower-like SnO2 (HFL-SnO2) nanostructures are successfully synthesized through the hydrothermal method. We find that the hierarchical architectures of SnO2 is assembled by a number of regular-shaped nanosheets, which are cross-linked in the interior of the micro-flower. The product also has a high specific surface area of about 78.8 m2g−1. Based on the nucleation and self-assembly process, a possible formation mechanism is proposed. The effects of SDS and NaCl on the product are also studied. Moreover, the product exhibits excellent photocatalytic activity and take possession of good stability and reusability under visible light. This study provides valuable experimental data for further study of nanomaterials and their photocatalytic properties.

Synthesis of hierarchical flower-like SnO2 nanostructures and their photocatalytic properties

SnO2 nanostructures were prepared successfully through a template-free and surfactant-free hydrothermal method. The prepared SnO2 nanostructures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectra and UV–vis absorption spectra. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. Furthermore, the possible growth and photodegradation mechanism of the as-prepared sample were also briefly discussed.

Synthesis of hierarchical SnO2 nanoflowers with enhanced acetic acid gas sensing properties

Different morphologies hierarchical flower-like tin dioxide (SnO2) nanostructures were fabricated by changing the volume ratio of glycol and de-ionized water (Vg:Vw=0, 1:2, 1:1 and 2:1) under a template-free and low-cost hydrothermal method and subsequent calcinations. The architectures, morphologies and gas sensing performances of the products were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and gas-sensing measurement device. It can be observed that all the nanoflowers were composed of two-dimensional (2D) nanosheets, and the thickness of nanosheets is only about 9nm when Vg:Vw=1:1. The sensor based on the product of Vg:Vw=1:1 exhibited excellent gas sensing performance toward 500ppm acetic acid at 260°C, and the response value of this sensor was about 153.6, which was above 7.5 times higher than that of ammonia (about 20.3). In addition, the 3D flower-like SnO2 nanostructures exhibited not only high response and selectivity to ppm level acetone, but also fast response and recovery time within 10s, demonstrating it can be used as a potential candidate for detecting acetic acid. Finally, the possible formation mechanism was proposed, too.

Synthesis and enhanced acetone sensing properties of 3D porous flower-like SnO2 nanostructures

The three-dimensional (3D) hierarchical SnO2 nanoflowers constructed by two-dimensional (2D) porous nanosheets were successfully fabricated by a one-step hydrothermal method and calcination procedure. The nanostructure and morphology of the hierarchical flower-like SnO2 were characterized by X-ray diffraction (XRD), energy dispersive X-ray detector (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. A possible formation process and growth mechanism for such fabricated 3D hierarchical SnO2 nanostructures have been proposed based on the experimental results. It is found that the flower-like SnO2 architectures were composed of many 2D porous nanosheets with the thickness about 20nm. In addition, the gas sensor based on this 3D hierarchical structure has an optimum operating temperature of 280°C, high sensitivity, quick response/recovery time and good selectivity for acetone.

Hydrothermal synthesis and structural properties of hierarchical flower-like SnO2 nanostructures for lithium ion batteries

In this work, a facile hydrothermal method has been used to prepare hierarchical flower-like SnO2 nanostructures without the assistance of any templates or surfactants. The obtained three-dimensional (3D) nanostructures are composed of two-dimensional (2D) nanosheets with smooth surfaces, which are endowed with a specific surface area of 46.7 m2 g−1. As lithium ion battery anodes, hierarchical flower-like SnO2 can interestingly present a high initial coulombic efficiency of 63.4 % and give the 40th reversible discharge capacity of 771.9 mAh g−1 at a current density of 160 mA g−1. Therefore, the 180 °C heat-treatment of aqueous mixture of tin dichloride and sodium hydroxide facilitates the mass production of nanostructured SnO2 for its potential application as lithium ion battery anodes.

Large scale synthesis of flower-like SnO2 nanostructures via a facile hydrothermal route

Materials with hierarchical architectures often exhibit novel functional properties. In this paper, the hierarchical SnO2 flower-like architecture, consisting of numerous aggregative nanosheets was successfully synthesized via a facile hydrothermal method and subsequent calcination. The structures and morphologies of this hierarchical architecture were characterized in detail by means of powder X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). Further comparative experiments show that the sodium citrate was benefit to promote the growth of SnO2 nanosheets and accelerate the assembling of nanosheets into flower-like architecture, the PEG provided nucleation sites and made the nanoflowers grow uniformly and separated. Moreover, a possible growth mechanism of the flower-like architectures was proposed. The non-trivial behavior of flower-like SnO2 may be driven by the properties of grain boundaries.

Porous flower-like SnO2 nanostructures as sensitive gas sensors for volatile organic compounds detection

Porous flower-like tin oxide (SnO2) nanostructure is prepared by annealing of the flower-like copper tin sulfur (Cu3SnS4) nanostructures. The morphology and crystal structure of the flower-like SnO2 nanostructures are characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The as-prepared porous flower-like SnO2 nanostructures exhibit a good response and reversibility to some organic vapors, such as toluene and formaldehyde. The sensing responses to 100 ppm of toluene and formaldehyde were 9.7 and 9.5, respectively. Moreover, the sensors exhibit a good response to benzene, methanol, ethanol, and acetone. The relationship between the gas-sensing properties and the microstructure of the as-prepared flower-like SnO2 nanostructures is also investigated.

Preparation of Flower-like SnO2 Nanostructures and Their Applications in Gas-Sensing and Lithium Storage

Hierarchical flower-like SnO2 nanospheres have been prepared by one step hydrothermal reaction with surfactant-free. A possible growth mechanism is proposed. The application of this nanostructure in gas sensor for detecting ethanol reveals that the as-prepared SnO2 nanospheres exhibit a high sensitivity and short response/recovery time. The flower-like SnO2 nanostructures were also used as anode materials for Li-ion battery, whose cyclic voltammetry, charge–discharge galvanstatic behavior and cycle performance were examined. For the sample with 6 h hydrothermal time, a highly stable capacity about 570 mA g–1 after 100 cycles is achieved. The gas sensing properties are mainly determined by the specific surface area, and the 3D nanostructured films composed of flower-like SnO2 nanospheres are favorable for the diffusion of gas molecules. At the same time, the high specific surface area of the flower-like SnO2 nanospheres can provide more electrochemical active sites for Li storage, and the 3D nanostructured films composed of this nanostructure facilitate the diffusion of electrolyte. Furthermore, the short rods on the nanospheres may provide a buffer to alleviate volume change during the alloying and dealloying reactions between Sn and Li. The superior properties achieved here suggest that the as-prepared hierarchical flower-like SnO2 nanostructures have potential application in Li-ion battery and gas sensor.