Flower-like SnO2 Research Articles

Flower-like SnO2 nanorod aggregates modified with Co3O4 nanoparticles grown on reduced graphene oxide(rGO) sheets for xylene sensing

In this paper, the ternary composite of flower-like SnO2 nanorod aggregates modified with Co3O4 nanoparticles grown on rGO sheets were synthesized by a two-step process of water heating and water bath, and characterized by SEM, TEM, XRD, EDS, and XPS. The gas-sensitive performance test results revealed that the 15-rGO/SnO2/Co3O4 sensor exhibited a higher response value (I0/Ia=24.46) to 100 ppm xylene at the optimal working temperature of 175℃. In addition, the sensor could detect 10 ppb xylene, with a low detection limit. The gas-sensitive properties of 15-rGO/SnO2/Co3O4 were significantly improved due to the large specific surface area of rGO flakes and SnO2 slender nanorods, the catalytic action of p-type semiconductor Co3O4 and the existence of p-n-p double heterojunction. Due to the special nanostructure and synergistic effect of SnO2, rGO and Co3O4, the 15-rGO/SnO2/Co3O4 sensor enabled the efficient and selective detection of xylene.

Combination of multiple routes to enhance DSSC performance: Flower-like structure of SnO2 as photoanode and modification with Ag nanoparticle

SnO2 is an attractive photoanode material for dye-sensitized solar cells (DSSCs), but it has many drawbacks and needs to be modified. In this study, flower-like SnO2 particles are firstly prepared by a simple one-step hydrothermal synthesis method respectively, and the effect of hydrothermal reaction time on the growth of the particles is explored. The morphological and structural characterisation reveals that the flower-like particles have a larger specific surface area can provide more adsorption sites for dye molecules and are more suitable for photoanode materials. Then the optimal flower-like SnO2 particles are selected to prepare the photoanode, which is also modified with different concentrations of Ag nanoparticles to successfully introduce the localized surface plasmon resonance (LSPR) effect, and the optimal modification concentration is explored. Conformal characterisation, dye adsorption and light absorption tests revealed that the modification of Ag nanoparticles not only optimises the photoanode conformal structure and improves the dye adsorption, but also works in conjunction with the LSPR effect to improve the light absorption and utilisation, thus increasing the cell efficiency. Many cell performances of DSSC are also greatly improved due to the above work, and the optimal cell performance of DSSC is achieved when the Ag nanoparticles doping concentration is 0.03 M. Compared with the pure flower-like SnO2-based photoanode DSSC, the short-circuit current density of the best Ag nanoparticle-modified DSSC is enhanced by 28.56% to 15.80 mA/cm2, and its efficiency is improved by 20.82%–5.92%.

Urchin flower-like SnO2 nanosheets anchored on waste biomass carbon as advanced anode for lithium-ion batteries

Although SnO2 is considered a desirable anode for lithium-ion batteries benefitting from its high theoretical capacity, yet the low electrical conductivity and associated volume expansion substantially hinder the commercialization. Here, urchin flower-like SnO2 nanosheets were anchored on biomass porous carbon material converted from spent disposable bamboo chopsticks via a simple strategy. The prepared SnO2@carbon material could be regarded as a superior anode in lithium-ion batteries. The SnO2@carbon anode delivered an initial specific capacity of 1182.5 mAh g−1 under a current density of 0.1 A g−1 and maintained 275.8 mAh g−1 at 3 A g−1, suggesting the prominent rate capability. Notably, the SnO2@AC anode exhibited 570.5 mAh g−1 after 500 cycles at 0.5 A g−1. The remarkable performances are attributed to the nano-size of SnO2, which shortens the ion transport length and increases the active sites. Besides, the porous carbon material as anchoring substrate boosts the overall conductivity, promotes electrolyte penetration, and buffers volume expansion. Finally, a highly reversible conversion reaction between Li2O/Sn and SnO2, and mitigation of the agglomeration of SnO2 could be realized. The work can provide potential inspiration for waste resource recovery and development of metal oxide-based conversion-type materials for energy storage.

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.

Flower-like tin oxide membranes with robust three-dimensional channels for efficient removal of iron ions from hydrogen peroxide

Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide (H2O2). But due to the oxidation degradation of the organic membranes (e.g. polyamide) by the strong oxidative radicals (e.g. OH) generated via the activation of H2O2 by iron ions (Fe3+), the short effective lifetime of membranes remains a challenge. Inorganic nano tin oxide (SnO2) has great potential for the removal of Fe3+ in strongly oxidative H2O2 because of its ability to stabilize H2O2 and preferentially adsorb Fe3+. Herein, we have designed for the first time a flower-like robust SnO2 membrane on the ceramic support by in situ template-free one-step hydrothermal method. The three-dimensional loose pore structure in the membrane built by interlacing SnO2 nanosheets endows the SnO2 membrane with a high specific surface area and abundant adsorption sites (OH). Based on the coordination complexation and electrostatic attraction between the SnO2 surface and Fe3+, the membrane shows a high Fe3+ removal efficiency (83%) and permeability (24 L·m−2·h−1·MPa−1) in H2O2. This study provides an innovative and simple approach to designing robust SnO2 membranes for highly efficient removal of Fe3+ in harsh environments, such as strong oxidation conditions.

Cu-doped flower-like SnO2 architecture toward promoting SO2 detection: Fast equilibrium and low trace monitoring

Design of practical tin oxide (SnO2) semiconductor gas sensors is fundamental strategy to detect hazardous gases such as SO2. However, challenges remain in the detection of SO2 gas at low concentration and slow equilibrium between gas adsorption and desorption. Herein, the superior performance of nanostructured of Cu-doped flower-like SnO2 architecture via feasible hydrothermal method demonstrated for the detection of SO2 gas at low concentration (1–20 ppm) and fast gas adsorption and desorption equilibrium (14 s) towards 5 ppm SO2. Furthermore, the as fabricated 3 mol% Cu-doped SnO2 shows an outstanding gas response (∼ 4.05–20 ppm SO2) at the working temperature of 300 ℃. The Cu-doping strategy may pave the way to ultrasensitive SO2 gas sensor possessing low trace monitoring and fast equilibrium ability to satisfy the increasing demand for toxic SO2 gas detection.

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.

Intercalated chitosan-ionic liquid ionogel in SnO nanoplate: band gap narrow and adsorption-photodegradation process

Ionogels are a category of hybrid material containing ionic liquid stabilized by polymeric network. These composites have some applications in solid-state, energy storage devices and environmental studies. In this research, chitosan (CS), ethyl pyridinium iodide ionic liquid (IL), and ionogel (IG) consisting of chitosan and ionic liquid were used in the preparation of a SnO nanoplate (SnO-IL, SnO-CS and SnO-IG). For the preparation of the ethyl pyridinium iodide, a mixture of pyridine and iodoethane (1: 2 molar ratio) was refluxed for 24 hours. The ionogel was formed using ethyl pyridinium iodide ionic liquid in chitosan that was dissolved in acetic acid (1 % v/v). By increasing NH3∙H2O, the pH of the ionogel reached 7‐8. Then, the resultant IG was mixed with SnO in an ultrasonic bath for 1 h. The microstructure of the ionogel was involved as assembled unit via π-π, electrostatic and hydrogen bonding interactions to be three-dimensional networks. The intercalated ionic liquid and chitosan influenced the stability of the SnO nanoplates and improved band gap values. When chitosan was contained as the interlayer space of the SnO nanostructure, the resulting biocomposite formed a well-ordered flower-like SnO structure. These hybrid material structures were characterized by FT-IR, XRD, SEM, TGA, DSC, BET, and DRS techniques. The changes in the band gap values for photocatalysis applications were investigated. In the case of SnO, SnO-IL, SnO-CS, and SnO-IG, the band gap energy was 3.9, 3.6, 3.2, and 2.8 eV, respectively. The dye removal efficiency of SnO-IG was 98.5, 98.8, 97.9, and 98.4 % via the second-order kinetic model for Reactive Red 141, Reactive Red 195, Reactive Red 198, and Reactive Yellow 18, respectively. The maximum adsorption capacity of SnO-IG was 540.5, 584.7, 1501.5, and 1100.1 mg/g for Red 141, Red 195, Red 198, and Yellow 18 dyes, respectively. Also, an acceptable result (96.47 % dye removal) was obtained with the prepared SnO-IG biocomposite for dye removal from textile wastewater.

Synthesis of flower-like S-doped SnO2 hierarchical structure for gas sensing application at room temperature

Ammonia is one of the most common gases in life, which is produced in industrial emissions and agricultural activities. Therefore, effective detection of ammonia at low concentrations is vital for human health. Tin disulfide (SnS2) by virtue of its physical affinity and high surface area has become a promising material for gas sensing applications. The flower-like S-doped SnO2 3D hierarchical structure was succeeded in preparation via a two-step method. A variety of methods such as XRD, SEM, and TEM were utilized to characterize the prepared materials for the investigation of their surface morphological characteristics and elemental content. The morphological characterization analysis indicated that the prepared material was a self-assembled hierarchical flower-like SnS2 modified by SnO2 nanoparticles. In addition, the results from the elemental composition analysis showed the existence of Sn, O, and S elements in the material. Through experiments, we further tested the sensitivity, selectivity, and long-term stability of the S-doped SnO2 gas-sensitive material against NH3 at room temperature, and analyzed its sensing mechanism. As a result, the S-doped SnO2 was tested with a response value of 3.6 for 50 ppm ammonia’s outstanding performance in terms of selectivity and long-term stability. This work highlights the advantages of flower-like S-doped SnO2 3D hierarchical structures for NH3 sensors.

Construction of flower-like hierarchical Ni-doped SnO2 nanosheets and their gas sensing properties for ethanol

Detecting ethanol is desirable in alcohol testing for safe driving.

Achieving highly-efficient H2S gas sensor by flower-like SnO2–SnO/porous GaN heterojunction

A flower-like SnO2–SnO/porous GaN (FSS/PGaN) heterojunction was fabricated for the first time via a facile spraying process, and the whole process also involved hydrothermal preparation of FSS and electrochemical wet etching of GaN, and SnO2–SnO composites with p–n junctions were loaded onto PGaN surface directly applied to H2S sensor. Meanwhile, the excellent transport capability of heterojunction between FSS and PGaN facilitates electron transfer, that is, a response time as short as 65 s and a release time up to 27 s can be achieved merely at 150 °C under 50 ppm H2S concentration, which has laid a reasonable theoretical and experimental foundation for the subsequent PGaN-based heterojunction gas sensor. The lowering working temperature and high sensitivity (23.5 at 200 ppm H2S) are attributed to the structure of PGaN itself and the heterojunction between SnO2–SnO and PGaN. In addition, the as-obtained sensor showed ultra-high test stability. The simple design strategy of FSS/PGaN-based H2S sensor highlights its potential in various applications.

TiO2 Hollow Spheres With Flower-Like SnO2 Shell as Anodes for Lithium-Ion Batteries

SnO2 is a promising anode material for lithium-ion batteries due to its high theoretical specific capacity and low operation voltage. However, its poor cycling performance hinders its commercial application. In order to improve the cycling stability of SnO2 electrodes, novel flower-like SnO2/TiO2 hollow spheres were prepared by facile hydrothermal method using carbon spheres as templates. Their flower-like shell and mesoporous structure highlighted a large specific surface area and excellent ion migration performance. Their TiO2 hollow sphere matrix and 2D SnO2 nano-flakes ensured good cycle stability. The electrochemical measurements indicated that novel flower-like SnO2/TiO2 hollow spheres delivered a high specific capacity, low irreversible capacity loss and superior rate performance. After 1,000 cycles at current densities of 200 mA g−1, the capacity of the flower-like SnO2/TiO2 hollow spheres was still maintained at 720 mAh g−1. Their rate capacity reached 486 mAh g−1 when the current densities gradually increase to 2,000 mA g−1.

Flower-like SnO2 Nanoparticle Biofabrication Using Pometia pinnata Leaf Extract and Study on Its Photocatalytic and Antibacterial Activities.

The present study reported biofabrication of flower-like SnO2 nanoparticles using Pometia pinnata leaf extract. The study focused on the physicochemical characteristics of the prepared SnO2 nanoparticles and its activity as photocatalyst and antibacterial agent. The characterization was performed by XRD, SEM, TEM, UV-DRS and XPS analyses. Photocatalytic activity of the nanoparticles was examined on bromophenol blue photooxidation; meanwhile, the antibacterial activity was evaluated against Klebsiella pneumoniae, Escherichia coli Staphylococcus aureus and Streptococcus pyogenes. XRD and XPS analyses confirmed the single tetragonal SnO2 phase. The result from SEM analysis indicates the flower like morphology of SnO2 nanoparticles, and by TEM analysis, the nanoparticles were seen to be in uniform spherical shapes with a diameter ranging from 8 to 20 nm. SnO2 nanoparticles showed significant photocatalytic activity in photooxidation of bromophenol blue as the degradation efficiency reached 99.93%, and the photocatalyst exhibited the reusability as the degradation efficiency values were insignificantly changed until the fifth cycle. Antibacterial assay indicated that the synthesized SnO2 nanoparticles exhibit an inhibition of tested bacteria and showed a potential to be applied for further environmental and medical applications.

Self-templated one-step hydrothermal synthesis of hierarchical actinomorphic flower-like SnO2-ZnO nanorods for high-performance supercapacitor application

• A unique actinomorphic flower-like SnO 2 nanostructure was synthesized via the one-step hydrothermal method. • Achieved high specific capacitance is 797.23 F/g at 1 A/g current density and capacitance retention is 88.2% and coulombic efficieny is 98.7 %. In this paper, we demonstrate the unique actinomorphic flower-like morphology of a tin oxide -zinc oxide (SZ) nanocomposite that has been synthesized using a one-step hydrothermal method and investigated for supercapacitor (SC) application. The optical, morphological and elemental composition features of pure SnO 2 and SZ nanocomposite were carried out by using different characterization techniques such as XRD, FTIR, FESEM, HRTEM, and XPS. The SZ-10 nanocomposite was the most significant one and was used in the fabrication of all solid-state symmetric supercapacitor. Electrochemical analysis of the Galvano charging-discharging (GCD) curves achieved a high specific capacitance (Csp) of 797.23 Fg −1 at a current density (CD) of 1 Ag −1 . The cyclic voltammetry (CV) curve for the SZ-10 electrode shows the high Csp of 548.56 Fg −1 at a scan rate of 10 mV/s. It has superior cyclic stability with capacitance retention of 88.2% and coulombic efficiency of 98.7%, even after 5000 repetitive cycles. The SZ-10 electrode also shows a high energy density (ED) of 45.72 Whkg −1 and a power density (PD) of 406 Wkg −1, at a CD of 1 Ag −1 . Furthermore, the fabricated SC device is linked in series to turn on a commercial red LED that glows for 1 to 2 min. These investigations demonstrate that the SZ-10 nanocomposite is an excellent electrode material for high-energy storage devices for SC applications.

Highly selective detection of ethanol based on hierarchical three-dimensional SnO2: Combining experiment with first-principles calculation

Improving gas sensing characteristics through the microstructure has attracted more and more attention in recent years. A hierarchical SnO2 nanostructure and its high ethanol selectivity were developed in this work. The hierarchical SnO2 nanostructure was obtained by a facile annealing process using SnS2 nanoflowers as precursor. The SEM and TEM results show that a flower-like SnO2 structure composed of nanoplates forms a hierarchical structure. The hierarchical SnO2 demonstrated excellent response time and high selectivity to ethanol at 200℃. The response/recovery time to 20 ppm ethanol vapor is about 0.75 s and 50 s, respectively. The enhanced sensing properties benefit from its unique structure, including the flower-like hierarchical structure and abundant surface defects, providing more gas active centers and diffusion paths. In order to understand the high selectivity, the first-principles calculations were carried out on the adsorption behavior between SnO2 and various gases. The result demonstrated that SnO2 was theoretically more selective in ethanol than other gases based on the adsorption energy. Humidity test and cycle test effectively prove that the sensor based on SnO2 nanoflower has great prospects for the detection of ethanol.

Tin(IV) oxide nanoparticulate films for aqueous dye-sensitized solar cells

Reported solar conversion efficiencies of aqueous dye-sensitized solar cells (DSSCs) trail those of traditional organic electrolyte-based systems but offer the potential for lower environmental impact and overall cost. Methods for improving the photochemical activity of aqueous DSSCs could also impact progress in related fields such as solar fuels and solar batteries. This work presents the first study solely focused on the use of SnO2-based photoanodes for use in aqueous DSSCs. Material design and interfacial engineering are critical to the effective use of SnO2 in this context, and it is found that mesoporous films comprised of both large 1–2 μm flower-like SnO2 particles and small 10–20 nm spherical SnO2 particles provide better performance than films composed of only one particle type. Insulating TiO2 coatings further improve the performance, and this work presents a facile liquid phase deposition strategy under ambient conditions using an aqueous TiF62- solution that proves more effective than the widely used method with TiCl4 for fabricating high-performing SnO2@TiO2 photoanode surfaces. The best aqueous DSSCs reported here using cis-bis(isothiocyanato)-bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) dye and simple I3-/I- electrolyte achieve a power conversion efficiency of 0.7% which eclipses the first reported TiO2-based DSSC using otherwise identical dye and electrolyte composition.

Coca-Cola solvothermal synthesis of mesoporous SnO2 blooming flower-like architecture assembled from single crystal nanorods and its gas sensing properties

The novel synthetic strategy for functional metal oxide nanomaterials by using biomass reaction media has recently attracted great attention. Herein, mesoporous SnO2 blooming flower-like architectures, assembled from single crystal nanorods with a diameter of 50–100 nm, were firstly prepared using Coca-Cola solvothermal route. In contrast, SnO2 microspheres were obtained by hydrothermal reaction. These indicate that the biomasses in Coca-Cola play a regulatory role in the formation of flower-like SnO2 hierarchical structure with uniform mesopore of 12.87 nm. The results of various gases tested show that the sensor based on blooming flower-like SnO2 structure has good performance towards H2S gas at optimum working temperature of 170 °C. The sensitivity to 10 ppm H2S gas is 118.4, being almost three times higher than that of SnO2 microspheres (40.9). The sensor shows good linear relationship ranging 0.05 to 10 ppm with lower detection limit (50 ppb) and good selectivity.

One-Step Synthesis of Hierarchical Flower-like SnO2/BiOCOOH Microspheres with Enhanced Light Response for the Removal of Pollutants.

The low separation rate of electron-hole pairs in single-component photocatalysts severely limits their applications for wastewater treatment. For this study, SnO2/BiOCOOH photocatalysts in flower-like microspheres were controllably synthesized via a one-step hydrothermal method and were characterized by various advanced techniques. These SnO2/BiOCOOH nanocomposites demonstrated excellent photocatalytic activities for the degradation of rhodamine B (RhB), titan yellow, and levofloxacin hydrochloride (LVF). Specifically, 98.5% of RhB, 80% of titan yellow, and 85% of LVF were degraded under 5 W LED (λ = 365 nm) light irradiation within 30, 40, and 60 min, respectively. Radical trapping experiments and electron spin resonance results indicated that h+ was the dominant active radical, whereas ·O2- and ·OH played an auxiliary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.

Synthesis and room-temperature H2S sensing of Pt nanoparticle-functionalized SnO2 mesoporous nanoflowers

Abstract Platinum nanoparticle (NP)-functionalized flower-like mesoporous SnO2 with a high specific surface area (31.6 m2g–1) and large pore diameter (32.5 nm) was synthesized using a double-template technique. The presence of Pt NPs was confirmed by X-ray photoelectron spectroscopy. Pt NPs with a size distribution of 2–4 nm were anchored on mesopores of the pre-synthesized three-dimensional SnO2 nanoflowers upon physical mixing. The resulting Pt NP-decorated three-dimensional SnO2 mesoporous nanoflowers were incorporated into a gas sensor to detect H2S. The Pt–SnO2 sensor exhibited enhanced gas sensing properties toward H2S, with a 100 ppb detection limit, fast response, low working temperature, excellent stability, and good selectivity. The 0.3 wt% Pt–SnO2 sensor exhibited a high response and excellent selectivity to H2S at room temperature (response value to 5 ppm H2S at 30 °C was 160). The significant improvements in gas sensing properties were attributed to the synergistic effect of the mesoporous nanostructure induced by the double-template method and the catalytic sensitization of the Pt NPs. These findings offer guidance for designing mesoporous materials and low-temperature H2S sensors.

Temperature-controlled resistive sensing of gaseous H2S or NO2 by using flower-like palladium-doped SnO2 nanomaterials.

Palladium-doped SnO2 nanomaterials, with palladium in fractions from 0 to 10mol% were hydrothermally synthesized and characterized by XRD, FESEM, TEM, and XPS. Their gas sensing properties were studied in two temperature ranges of 75-95°C and 160-210°C. The sensor using 5mol% Pd-doped SnO2 exhibits temperature-dependent sensing property. NO2 can be detected at 80°C, while H2S is preferably detected at 180°C. The response to 10ppm H2S is 50 times higher than that of the undoped sample. Its detection limit is 500ppb. For NO2, the sensor exhibited strong response and a lower detection limit of 20ppb. In view of the selective detection of H2S and NO2 by regulating the temperature, palladium-doped SnO2 has great prospects in the detection of H2S and NO2. Graphical abstract Schematic of the gas sensing mechanism of the S-5% Pd doped SnO2.