Growth Of SnO2 Nanoparticles Research Articles

In-situ confinement of ultrasmall SnO2 nanocrystals into redox-active polyimides for high‐rate and long-cycling anode materials

SnO2 as a promising anode material possesses a high theoretical capacity and a safe lithiation potential; however, it suffers from low cycle stability and poor rate capability due to its nano-aggregation effect, structural instability, and sluggish electrode kinetics. Herein a one-pot hydrothermal process was developed to craft ultrasmall SnO2 nanocrystals uniformly encapsulated in the polyimide matrix through a facile in-situ polymerization. The polyimide phase can suppress the over growth of SnO2 nanoparticles while preventing from their re-aggregation through the space-confined effect during the material synthesis. The robust polyimide matrix can be also served as a protective layer to relieve the volume change of SnO2 nanoparticles and inhibit the cracks propagation throughout the whole electrode during the charge/discharge processes. Moreover, the carbonyl-contained polyimide is intrinsically redox-active, capable of affording acceptable ionic conduction ability. Remarkably, the as-fabricated SnO2@PI composite anode exhibits a reversible capacity as high as 897 mAh g−1 at 0.1 A g−1 and a high rate capability (479 mAh g−1 at 2.0 A g−1) with a higher retention (53%) than pure SnO2 (39%). The SnO2@PI anode also retains a capacity of 653 mAh g−1 at 0.5 A g−1 after 150 cycles. This work would offer an alternative strategy by incorporating metal oxide nanoparticles into the redox-active polymer matrix for advanced anode materials with high rate capability and long-term cyclability.

Oxygen doped activated carbon/SnO2 nanohybrid for high performance lithium-ion capacitor

Oxygen doped activated carbon (OAC) is synthesized through chemical activation and nitric acid oxidation. The OAC/SnO2 composite is prepared by a novel vacuum melting method. With this approach, SnO2 nanoparticles are effectively doped into the nanoporous of OAC and enhance the bonding properties between OAC and SnO2, which will avoid the aggregation and growth of SnO2 nanoparticles during the long charge-discharge process. After 800 cycles at 500 mA g−1 as electrode materials for half cells, the OAC/SnO2 exhibits a higher reversible capacity (927 mAh g−1). Under the condition of 787 W kg−1, the hybrid-type lithium ion capacitor assembled using the OAC/SnO2 and nitrogen doped activated carbon electrode delivers a high energy density of 151 Wh kg−1. The hybrid device also shows high cycle performance (93% capacity retention after 9000 cycles) at 2.0–4.5 V.

Exceptional anodic performance of Sb-doped SnO2 nanoparticles on electrochemically exfoliated graphene for lithium-ion batteries

Metal oxides such as SnO2 are widely studied as anode materials for next-generation lithium-ion batteries because of their high theoretical capacities. However, the lithium storage capability of SnO2 is suppressed by its poor electrical conductivity and serious volume change during the charge and discharge processes. In this work, SnO2 nanoparticles are directly grown on the surface of electrochemically exfoliated graphene, followed by doping Sb into SnO2 nanoparticles. As a high quality of graphene, electrochemically exfoliated graphene possesses high electrical conductivity and strong mechanical strength, which is beneficial to the charge transfer from graphene to SnO2 nanoparticles. Moreover, the doping of Sb into SnO2 nanoparticles inhibits the agglomeration and growth of SnO2 nanoparticles, and further improves the electron conductivity of SnO2 by changing the electronic structure of SnO2. As a result, electrochemically exfoliated graphene-based SnO2 with Sb doping exhibits superior electrochemical performance including high reversible capacity, excellent cycling stability and remarkable rate capability. Modifying the electronic structure of metal oxides by doping with appropriate metals may provide an avenue to realize the demand of high-performance electrodes for secondary batteries.

Ion Exchange in Sodium Titanate Nanoribbons and its Application in Dye Photodegradation of Remazol Blue

This work addresses the main point, the synthesis of one-dimensional titanate nanostructures and their ion exchange with transition metals for application in photocatalysis. The catalysts tested in the photocatalytic process were titanate nanoribbons (NRTi) synthesized by hydrothermal method and ion exchanged with Sn2+. The structural and morphological analysis of the material was performed by XRD, Raman spectroscopy and TEM images, confirming the formation of the desired structures and the growth of SnO2 nanoparticles after the ion exchange process with average size smaller than 10 nm. The values of surface area were obtained by BET and showed a significant increment after the ion exchange process, making it favorable for application in photocatalysis. The NRTi was applied in the degradation of blue dye remazol, generating a total degradation in 120 minutes. The rate constants were calculated from the pseudo-first-order equation.

Crystallinity and morphology-controlled synthesis of SnO2 nanoparticles for higher gas sensitivity

SnO2 nanoparticles with controlled crystallinity, morphology and gas sensitivity have been synthesized by four modified wet chemical processes using the same granular Sn but different solvents and preparation routes. The thermal decomposition, crystalline phase, morphology and gas sensitivity of precursors and well-crystallized SnO2 nanoparticles were characterized by means of differential thermal analysis, X-ray diffraction, scanning electron microscopy, field emission transmission electron microscopy, energy dispersive X-ray spectroscopy and gas sensitivity measurement system. Results indicated that SnO2 precursors showed quite different endothermic heat behavior, crystallinity and particle size, which were strongly depended on preparation processes. SnO2 nanoparticles from different precursors showed the same typical tetragonal rutile SnO2 structure but different particle size and morphology. The gas sensitivity of SnO2 nanoparticles was investigated, which was strongly correlated with SnO2 nanoparticles. At last, the formation mechanism including nucleation and growth of SnO2 nanoparticles was proposed based on wet chemical reaction equations.

Simple route for synthesis of tin dioxide nanorods based on improved solid state reactions

A synthesising method is reported with an enhanced solid state reaction to fabricate SnO2 nanorods. The structure and morphology of the SnO2 nanorods were characterised by X-ray diffraction and transmission electron microscopy. The results showed that the nanorods were rutile SnO2 with a diameter of ∼30 nm and length of several micrometres. It was found that chlorine salt was very important for controlling the grain size of nanoparticles and providing kinetic and ambulatory circumstance to induce oriented growth of SnO2 nanoparticles. The growth mechanism of the nanorods can be understood on the basis of oriented aggregation induced by polar forces.

Grain Size Control of Calcined SnO<SUB>2</SUB> Nanocrystals: Raman Study and Room Temperature Ethanol Sensing Properties

SnO2 nanoparticles were prepared via a sol-gel method by heating the mixture of hydrous SnO2 nanoparticles and SiO2 nanospheres at 600 degrees C. The average particle size of the obtained SnO2 nanoparticles is 3.3 nm, smaller than that of the SnO2 nanoparticles ( 6.4 nm) prepared by calcining the pure hydrous SnO2 at 600 degrees C. The restricting effect of SiO2 on the growth of SnO2 nanoparticles was discussed by Raman spectra. A blue shift of A1g ) and B2g Raman modes in SnO2/SiO2 composite was observed, and it was considered to be a compressive stress effect. The obtained SnO2 nanoparticles with a size of about 3.3 nm exhibit enhanced ethanol response at room temperature, and their recovery time is much shorter than that of the SnO2 nanocrystals with a size of about 6.4 nm.

Formation and growth of SnO2 nanoparticles in silica glass by Sn implantation and annealing

Nanocrystalline Sn particles have been formed in silica glass through 50 keV Sn− implantation followed by annealing in N2 at 650 °C for 30 min. Samples prepared this way have been annealed in air for 1 h, separately at four different temperatures, 400, 600, 800, and 1000 °C, each at a given temperature. Annealing at temperatures higher than 400 °C has been found to result in oxidation of the Sn nanoparticles (NPs) and formation of the SnO2 phase as confirmed from optical absorption (OA), transmission electron microscopy, and Raman scattering measurements. For the sample annealed at 600 °C, Raman scattering data showed three bands at about 525, 629, and 771 cm−1, the last two corresponding to the A1g and B2g classical Raman modes of rutile SnO2. Increase in annealing temperature resulted in an increase in the intensities of the A1g and B2g modes showing better crystallinity. Also, the A1g peak shifted toward a higher wave number with a steady decrease in the intensity at 525 cm−1. This is in line with the growth in size of NPs as well as a reduction in the surface disorder. The Urbach tail width derived from the OA data also agrees with this.