Hierarchical Flower-like SnO2 Research Articles

Hydrothermal Synthesis of Novel Hierarchical Flower-Like SnO₂ with Enhanced Visible-Light-Driven Photocatalytic Activity.

The novel hierarchical flower-like SnO₂ (HFL-SnO₂) nanostructures with the diameter of about 500 nm, which are composed of regular-shaped nanosheets, are synthesized with a solvothermal method in the presence of 1 ml of Triethylamine (TEA) and the 0.2 mmol of Hexamethylene tetraamine (HMT) at 160 °C for 6 h. The SnO₂ has a high specific surface area of about 38.5 m²g-1. Based on the nucleation and self-assembly process, possible formation process of the new hierarchical flower-like nanostructures can be presented. The effects of TEA and HMT on the product are also studied. In addition, the product exhibits excellent photocatalttic activity to Methyl orange (MO) aqueous solution and possess good stability and reusability under visible light. This study will provide valuable experimental data for further study of nanomaterials and their photocatalytic properties.

Hydrothermally prepared porous 3D SnO2 microstructures for methane sensing at lower operating temperature

Porous three-dimensional (3D) hierarchical flower-like SnO2 nanomaterials were successfully synthesized via facile hydrothermal method combined with subsequent annealing process. Characterization analysis shows that the porous 3D SnO2 consists of a number of thin nanosheets with pores. Gas sensing properties indicate that the porous 3D SnO2 sensor has lower initial response temperature and optimal working temperature, better linearity in a certain range of gas concentration, better stability and selectivity to methane. Implies that porous 3D SnO2 nanomaterials will be promising candidates for methane sensors.

Synthesis of g-C3N4 nanosheets decorated flower-like tin oxide composites and their improved ethanol gas sensing properties

The g-C3N4 nanosheets decorated three-dimensional (3D) hierarchical flower-like SnO2 nanocomposites were synthesized via a facile hydrothermal method by using the g-C3N4 and SnCl2·2H2O as the precursors. The structure and morphology of the as-synthesized samples were characterized by the X-ray powder diffraction (XRD), electron microscopy (FESEM and TEM), N2 sorption, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FT-IR) techniques. It is supposed that g-C3N4 nanosheets act as a template in the hydrothermal process, accelerating the preferential growth of SnO2 nanocrystals and preventing the agglomeration of the SnO2 nanoparticles. The gas sensing performances of the as-synthesized samples to ethanol vapor were tested, and the response of the sensor based on 3 wt.% g-C3N4 decorated SnO2 composite to 500 ppm ethanol vapor was 360 at 300 °C, which was much higher than that of pure flower-like SnO2 based sensor. The improved ethanol gas sensing property is proposed to relate to the good conductivity of g-C3N4, high specific surface area and interactions between g-C3N4 and SnO2.

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 3D Flower-Like SnO2 with Hierarchical Nanostructure and High Reversible Capacity as Lithium-Ion Battery Anode

We report a route for large-scale synthesis of three-dimensional flower-like SnO2 microspheres. The prepared material was composed of special wedge-shaped nanorods with tetragonal and smooth square end planes. The obtained samples were characterized by x-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy. A formation mechanism is proposed. The morphological evolution of a SnO2 sample from hierarchical flower-like microspheres to nanorods was observed. Time-dependent experiments illustrated that the hydrothermal reaction time and stirring time of the precursor were two key factors affecting the SnO2 shape. Compared with unorganized nanoparticles, the hierarchical flower-like SnO2 microspheres exhibited a significant improvement in electrochemical performance as the anode material for Li-ion batteries. The initial discharge capacity reached 1610.5 mAh g−1. In view of its unique structure, the prepared material is also expected to find interesting applications in other fields such as gas sensing or photocatalysis.

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.

One-pot synthesis and improved sensing properties of hierarchical flowerlike SnO2 assembled from sheet and ultra-thin rod subunits

Self-assembled unusual SnO2 flowers have been synthesized by a facile one-pot hydrothermal route. FESEM and TEM reveal that these hierarchical SnO2 flowers, ranging from 600 to 900nm in size, are composed of two types of building blocks, that is, nanosheets and nanorods. Experimental results obtained from the different growth stages demonstrate that the as-prepared SnO2 nanostructures exhibit an interesting time-dependent evolution of building blocks, from sheets to ultra-thin rods with diameters down to 5nm. The possible formation mechanism for the hierarchical nanostructures with various architectures is presented on account of the self-assembled growth induced by Ostwald ripening. Furthermore, the as-prepared SnO2 nanosheets and nanorods exhibit improved acetone performances in comparison with hierarchical SnO2 nanosheets due to the additional presence of ultra-thin rodlike subunits. It is found that flowerlike SnO2 have a response of 11.4–50ppm acetone at the optimal operating temperature of 310°C, and the response and recovery time are within 1.6 and 7.0s, respectively.

Synthesis of multifarious hierarchical flower-like SnO2 and their gas-sensing properties

We successfully synthesized variant hierarchical assembled flower-like SnO2 via a simple hydrothermal technique and subsequent calcination. The structures and morphologies of the 3D nanostructures were investigated by means of powder X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The formation mechanism of these materials were proposed in detail. The gas-sensing performances of the as-prepared SnO2 were investigated towards ethanol. It is noted that the flower-sheet SnO2 sensor displayed particular response to the target gas, rendering SnO2 as a potential gas-sensing material for a broad range of future sensor applications.

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.

SnO2-Based Hierarchical Nanomicrostructures: Facile Synthesis and Their Applications in Gas Sensors and Lithium-Ion Batteries

Hierarchical flower-like SnO2 nanomicrostructure has been synthesized via a solvent-induced and surfactant assisted self-assembly technique at ambient temperature followed by a suitable thermal treatment. A possible growth mechanism governing the formation of such a nanomicrostructure is discussed. The applications in gas sensors for detecting CO and H2 reveal that the obtained SnO2 material exhibits a remarkable sensitivity and extremely low detecting limit (5 ppm), as well as good reproducibility and short response/recovery times, which benefit a lot from its unique flower-like nanomicrostructure consisting of three-dimensional interconnected SnO2 nanoparticles and nanopores. In order to use the present SnO2 nanomicrostructure in lithium-ion batteries, carbon coatings are introduced to the surface of them by pyrolysis of glucose under hydrothermal conditions. Both SnO2−C and Sn−C nanocomposites are obtained by taking thermal treatment of the precursors at different temperatures. The conversion processes...