Single-crystalline SnO2 Nanorods Research Articles

Performance of hybrid SnO2/Li2FeMn3O8 nanostructured electrode for efficient Li ion storage application

Li2FeMn3O8 (LFMO) nanocomposite material for Li-ion battery is synthesized using chemical combustion method. To fabricate a hybrid nanostructure electrode, LFMO is coated on tin oxide (SnO2) nanorods (NR), which is grown using a vapor-liquid solid (VLS) technique on a steel substrate. The surface morphology of the hybrid nanostructure electrode confirms that, single crystalline SnO2 nanorods are grown vertically with spine-like structures, a few microns in length, as evident from field emission scanning electron microscope image. The electrochemical performance of SnO2/LFMO shows very interesting characteristic with enormous charge storage capability. The coin cell shows improved capacity with a higher number of charging and discharging cycles. This SnO2/LFMO hybrid composite electrode shows better specific capacitance value as compared to the pristine SnO2 electrode.

Single crystalline SnO2 nanorods functionalized with TiO2 nanospheres and their electrochemical properties

Single crystalline SnO2 nanorods coated with TiO2 nanoparticles was synthesised using a two step solvothermal method. The structural and morphological characterizations were done using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The SEM micrographs show that the nanorods are uniformly coated with TiO2 nanoparticles. The elemental composition is determined from the EDAX spectrum. The TEM micrographs reveals that the SnO2 nanorods are single crystalline and formed along (110) direction and breadth wise along (101) direction. The electrochemical properties of both pure SnO2 and SnO2-TiO2 nanocomposite were investigated using cyclic voltammetry and electrochemical impedance spectroscopy, indicating that the chemical changes occurring at the electrode surface is a coupled reaction involving electron transfer followed by a reversible chemical reaction. The high reversibility and hence pseudocapacitive behaviour is confirmed as there is no significant shift in the anodic and cathodic peak currents with increasing scan rate. The slope of the plot of log i versus log v is varying from 0.9 to 1 further confirming excellent pseudocapacitance. A significant increase in the specific capacitance is observed for SnO2-TiO2 nanocomposite compared to pure SnO2.

A facile and one step synthesis of large surface area SnO2 nanorods and its photocatalytic activity

High quality single crystalline SnO2 nanorods (NRs) were successfully synthesized by using novel microwave-irradiation method by using PEG-400 as surfactant. Powder X-ray diffraction (XRD) results reveals that the SnO2 crystalline with tetragonal rutile type structure (space group P42/mnm) have formed directly during the microwave irradiation process. The results are good in agreement with the standard JCPDS data (file no. 41-1445). Transmission electron microscope (TEM) images showed that NRs of about 460–530 nm in length and 55–75 nm in diameter. UV–visible diffusion reflectance spectroscopic (DRS) studies exposed the band gap energies of SnO2 was found to be 3.27 and 2.58 eV for without and with PEG respectively. The photocatalytic activity study showed that the as-synthesized SnO2 NRs were superior photocatalytic performance for the degradation of methylene blue (MB) and rhodamine B (RhB) dye solutions. The samples were further characterized by photoluminescence and energy dispersive spectra analysis.

Liquid-liquid interface assisted synthesis of SnO2 nanorods with tunable length for enhanced performance in dye-sensitized solar cells

Single-crystalline SnO2 nanorods with tunable length are synthesized via a facile and surfactant-free solvothermal route based on an aqueous–organic solvent system. The length of the nanorods can be facilely controlled by adjusting the solvent ratio. Particularly, the average length increases from 14.6 to 98.0nm when the volume ratio of cyclohexane to water is varied from 20:30 to 49:1. The morphological evolution of the SnO2 nanorods is systematically investigated, and a growth mechanism involving three stages of nucleation, rearrangement and oriented growth is proposed, based on the free migration of the nanoparticles at the two immiscible interfaces thereby offering special path for the self-assembly. The synthesized SnO2 nanorods are used as photoanodes for dye-sensitized solar cells (DSSCs) and the photovoltaic performance is studied as a function of the morphology. UV–vis absorption spectra show the dye-loading capabilities of the DSSCs are gradually weaken with the length increase of the SnO2 nanorods. Electrochemical impedance spectroscopy analysis indicates that the charge transfer resistances at the SnO2/dye/electrolyte interfaces decrease and the electron lifetimes increase along with the increase of nanorod-length. As a consequence, DSSCs fabricated from medium-sized nanorods achieve the best power conversion efficiency of 3.50% due to the equilibrium between fast electron transport and large specific surface area.

Microwave-assisted synthesis of SnO2 nanorods for oxygen gas sensing at room temperature

High-quality single-crystalline SnO2 nanorods were synthesized using a microwave-assisted solution method. The nanorods were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible and Raman spectroscopy, Brunauer–Emmett–Teller (BET), and electrical resistance measurements. The XRD pattern indicated the formation of single-phase SnO2 nanorods with rutile structure. FE-SEM and TEM images revealed tetragonal nanorods of about 450–500 nm in length and 60–80 nm in diameter. The nanorods showed a higher BET surface area of 288 m2/g, much higher than that of previously reported work. The Raman scattering spectra indicated a typical rutile phase of the SnO2. The absorption spectrum showed an absorption peak centered at 340 nm, and the band-gap value was found to be 3.64 eV. The gas-sensing properties of the SnO2 nanorods for oxygen gas with different concentrations were measured at room temperature. It was found that the value of resistance increased with the increase in oxygen gas concentration in the test chamber. The SnO2 nanorods exhibited high sensitivity and rapid response-recovery characteristics to oxygen gas, and could detect oxygen concentration as low as 1, 3, 5, and 10 ppm.

Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP) immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM−1 cm−2), low detection limit (0.2 μM) and high selectivity with the apparent Michaelis–Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors.

Hierarchical SnO2 Nanostructures: Linear Assembly of Nanorods on the Nanowire Backbones

Single-crystalline SnO2 nanorods were successfully assembled on SnO2 nanowire backbones through a sequential gold-catalyzed thermal evaporation method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies showed that uniform secondary nanorod branches were epitaxially grown from two side surfaces of the nanowire backbones. These branch rods are parallel to each other with 2-fold symmetry with respect to the backbones. The crystal structure of these as-prepared SnO2 centipede-like nanostructures was identified to coincide to the normal rutile structure. The photoluminescence (PL) properties of single centipede-like SnO2 structures were studied by confocal microscopy, which showed that these structures can act as good optical waveguides. Cathodoluminescence (CL) spectra of the SnO2 branched structures obtained in the SEM−CL system featured a blue emission band around 462 nm that is attributed to a defect-state-related emission.

Synthesis and characterization of single crystalline SnO2 nanorods by high-pressure pulsed laser deposition

Tin oxide (SnO2) nanorods were grown by high-pressure pulsed laser deposition (PLD). The nanorods were grown without the use of a catalyst but required high background pressure growth in order to realize small grain columnar growth and nanorod formation, with nanorod formation most favored on non-epitaxial substrates. The structures and morphology were characterized by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). X-ray diffraction and HRTEM analysis indicate that the as-grown SnO2 nanorods are single crystals with a rutile structure. The nanorods are approximately 50–90 nm in diameters and 1.5 μm in length. This method provides an approach for large area synthesis of one dimensional SnO2 nanostructure materials.

Synthesis and ethanol sensing characteristics of single crystalline SnO2 nanorods

In a basic water-alcohol mixing solution without any other toxically organic solvents, the single crystalline SnO2 nanorods with diameters of 4–15 nm and lengths of 100–200 nm were synthesized using SnCl4 as a precursor. The sensors fabricated from the nanorods exhibited the sensitivity of 31.4 for 300 ppm of ethanol. Both the response and recovery time are short, around 1 s. Moreover, a linear dependence of the sensitivity on the ethanol concentration was observed. These behaviors were well explained by considering the high surface-to-volume ratio of the nanorods.

Large-Scale, solution-phase growth of single-crystalline SnO2 nanorods.

Small-diameter (<5 nm), single-crystalline SnO2 nanorods were synthesized in solution with a mean length of 17 +/- 4 nm (mean aspect ratio of 4:1) with the [001] direction along the major axis. Two characteristic peaks at 576 and 356 cm-1 in the Raman spectrum further confirmed the small crystal size. The SnO2 nanorods exhibit a red emission at 580 nm.