SnO2 Graphene Research Articles

Proton-irradiation on graphene-SnO2 hybrid nanocomposites to boost NO2 gas sensing properties

Promising role of high-energy proton-irradiation (2 MeV) on graphene-SnO2 hybrid nanocomposites for NO2 sensing were demonstrated. We synthesized hybrid nanocomposites by using SnO2 nanoparticles and graphene flakes, being obtained from expandable graphite. NO2 gas sensing evaluations, with doses of 1 × 1012, 1 × 1013, and 1 × 1014 ions/cm2, displayed that the sensing device irradiated with a dose of 1 × 1013 ions/cm2 exhibited the highest performance at 200 °C. Generation of structural defects and graphene-SnO2 heterojunctions were accounted for sensing enhancement. Calculations in regard to density functional theory revealed that the presence of defects enhanced the NO2 sensing of the optimized sensor. Besides considering defects in the graphene, we calculated the generation of SnO2-related defects, indirectly affecting the sensing characteristics.

Research progress of nano-modified materials for positive electrode of lithium-ion battery

Energy is an essential element in human production and life. In the context of today's energy shortage and increasingly serious environmental problems, electric vehicles have gradually begun to occupy the mainstream market, and improving the performance of electric vehicle batteries has become a hot topic for researchers. Today's electric cars generally use lithium-ion batteries. In this paper, the research progress of nano-scale material modification of lithium-ion battery cathode materials was explored, especially the modification of LiFePO4 and NCM ternary materials. For LiFePO4, the preparation process of nanoscale LiFePO4 was explored. Carbon nano-modified materials, such as nano-graphite, CNCs, and modified LiFePO4 cathode materials are also mentioned. For NCM ternary materials, the oxide nanomaterials, lithium salt nanomaterials, and carbon nanomaterials modified ternary cathode materials were explored. Among them, the oxide nanomaterials include Al2O3 and SiO2, the lithium salt nanomaterials include LiAlO2, LiNbO3, Li2TiO3, and Li2ZrO3, and the carbon nanomaterials include CNTs, graphene and graphene-oxide SnO2. After investigation, it was found that these nano-scale modified materials can improve the electrochemical performance of lithium-ion battery cathode materials.

Reactive Oxygen Species (ROS) Are Generated as Organic Contaminants Are Broken Down: SnO2-Doped Graphene Oxide Nanocomposites Are Investigated Under Visible Light Illumination for their Photocatalytic Activity

Our aim is to establish a more efficient and reliable method for the bio-fabrication of pure SnO2 and SnO2-doped graphene oxide nanocomposites through a green chelating agent called Moringa Oleifera extract by sol-gel method. A sintered SnO2-doped GO nanocomposite exhibited increased crystallinity and size with increasing temperature, as determined by XRD studies. An FTIR investigation shows that the SnO2-doped GO nanocomposite exhibits two distinct bands at 733 cm−1 and 438 cm−1 due to terminal oxygen vibrations, while samples treated with G-O-Sn-O exhibit bands at 733 cm−1 due to antisymmetric stretching. By increasing the SnO2 peak, SnO2 nanoparticle sizes decrease, which results in a broadened GO, as well as a reduced IR intensity. By SEM and EDAX, the size and morphology of SnO2-doped GO nanocomposites were clearly observed. It was calculated that the optical bandgap of SnO2-doped GO nanostructures is 4.48 eV. It has been demonstrated that SnO2-doped GO nanocomposite can be used as an organic photocatalyst against organic pollutants methyl orange (MO) dye; despite its fast charge recombination when illuminated with visible light, these findings have been reported in detail.

Dual recognition elements for selective determination of progesterone based on molecularly imprinted electrochemical aptasensor

A novel molecularly imprinted electrochemical aptasensor (MIEAS) was constructed for selective progesterone (P4) detection based on SnO2-graphene (SnO2-Gr) nanomaterial and gold nanoparticles (AuNPs). SnO2-Gr with a large specific area and excellent conductivity improved the adsorption capacity of P4. Aptamer, as biocompatible monomer, was captured by AuNPs on modified electrode through Au-S bond. An electropolymerized molecularly imprinted polymer (MIP) film consisted of p-aminothiophenol as chemical functional monomer and P4 as template molecule. Due to the synergetic effect of MIP and aptamer towards P4, this MIEAS exhibited better selectivity than the sensor with MIP or aptamer as single recognition element. The prepared sensor had a low detection limit of 1.73 × 10−15 M in a wide linear range from 10−14 M to 10−5 M. Satisfactory recovery obtained in tap water and milk samples proved that this sensor had great potential in environmental and food analysis.

Three-Dimensional Graphene-TiO2-SnO2 Ternary Nanocomposites for High-Performance Asymmetric Supercapacitors.

Ternary nanocomposites synergistically combine the material characteristics of three materials, altering the desired charge storage properties such as electrical conductivity, redox states, and surface area. Therefore, to improve the energy synergistic of SnO2, TiO2, and three-dimensional graphene, herein, we report a facile hydrothermal technique to synthesize a ternary nanocomposite of three-dimensional graphene-tin oxide-titanium dioxide (3DG-SnO2-TiO2). The synthesized ternary nanocomposite was characterized using material characterization techniques such as XRD, Raman spectroscopy, FTIR spectroscopy, FESEM, and EDXS. The surface area and porosity of the material were studied using Brunauer-Emmett-Teller (BET) studies. XRD studies showed the crystalline nature of the characteristic peaks of the individual materials, and FESEM studies revealed the deposition of SnO2-TiO2 on 3DG. The BET results show that incorporating 3DG into the SnO2-TiO2 binary nanocomposite increased its surface area compared to the binary composite. A three-electrode system compared the electrochemical performances of both the binary and ternary composites as a battery-type supercapacitor electrode in different molar KOH (1, 3, and 6 M) electrolytes. It was determined that the ternary nanocomposite electrode in 6 M KOH delivered a maximum specific capacitance of 232.7 C g-1 at 1 A g-1. An asymmetric supercapacitor (ASC) was fabricated based on 3DG-SnO2-TiO2 as a positive electrode and commercial activated carbon as a negative electrode (3DG-SnO2-TiO2//AC). The ASC delivered a maximum energy density of 28.6 Wh kg-1 at a power density of 367.7 W kg-1. Furthermore, the device delivered a superior cycling stability of ∼97% after 5000 cycles, showing its prospects as a commercial ASC electrode.

Mass ratio-dependently tunable enhancement of the optical nonlinearities of SnO2/RGO composites

The composite of graphene and semiconductor nanoparticles has attracted increasing interest in the search for novel nonlinear optical materials. Herein, composites of reduced graphene oxide (RGO) and SnO2 nanoparticles with different mass ratios were synthesized via a facile hydrothermal method. The structural morphology and basic physical properties of the SnO2/RGO composites were characterized using TEM, SEM, XRD, Raman, XPS and UV–Vis spectra, indicating that SnO2 nanoparticles were uniformly anchored on the surface of graphene nanosheets through covalent and partial-ionic bonds. The third-order optical nonlinearities of the composites were studied for the first time by the Z-scan technique using a picosecond laser at 532 nm. It was found that the composites demonstrated saturable absorption and positive nonlinear refraction properties, and both were significantly enhanced compared with pure SnO2 nanoparticles and RGO nanosheets, and the enhancement was tunable with the variation of SnO2:GO mass ratio. The maximum saturable absorption coefficient and the third-order susceptibility of the as-prepared SnO2/RGO composites were obtained to be −2.93×10–11 m W−1 and 2.25 × 10–11 esu, respectively. The maximum saturable absorption modulation depth obtained was 10% with the corresponding saturation light intensity of 0.3 GW cm−2. Moreover, the optimised third-order susceptibility of SnO2/RGO was found much greater than many other materials ever studied. Several involved factors contributing to the nonlinearities were discussed. The results propose that the third-order optical nonlinearities of SnO2/RGO and other similarly structured composites can be potentially tuned to meet certain application requirements of nonlinear optical devices by controlling the mass ratio of semiconductor to graphene.

Construction of rGO-SnO2 heterojunction for enhanced hydrogen detection

Sandwich-structured rGO-SnO2 nanocomposites comprising of reduced graphene oxide (rGO) nanosheets and SnO2 nanoparticles were prepared by a simple refluxing reaction, and its hydrogen sensing performance was investigated. The structural characterization confirmed that the ultra-fine cylindrical SnO2 nanoparticles with length of ∼ 15 nm and diameter of ∼ 5 nm were loaded on the surface of rGO nanosheets. BET surface area of rGO-SnO2 nanocomposite enhanced as the amount of GO increased. Additionally, the increase in the amount of GO effectively inhibited the disproportionation reaction of Sn2+ during the annealing process. When the mass ratio of GO to SnO2 was higher than 1.0 wt%, the disproportionation reaction of Sn2+ was completely suppressed and all Sn-related products were changed into SnO2 phases. The 1.0 wt% rGO-SnO2 nanocomposites based gas sensor showed the highest response of 11.88 to 500 ppm H2 at 225 °C, with fast response/recovery times of 2 s/19 s and a detection limit of lower than 5 ppm. Especially, the sensor showed good reproducibility, selectivity, moisture resistance, and long-term stability. H2 sensing mechanisms of rGO-SnO2 nanocomposites were discussed based on the experimental data and gas-sensing reaction theory.

Preparation and Electrochemical Performance of Reduced Graphene and SnO2 Nanospheres Composite Materials for Lithium‐Ion Batteries and Sodium‐Ion Batteries

AbstractSnO2 has been considered a promising anode material for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) owing to the high capacity, and environmental friendliness. In this study, a mixture of reduced graphene oxide and SnO2 nanospheres (SnO2 NPs) was prepared via a simple method in the solution of graphene oxide (GO), Vitamin C and SnO2. Vitamin C plays an important role in reducing graphene oxide. In addition, graphene can alleviate volume changes of SnO2 as host and induce effective charge transfer through its interconnected network structure. As a consequence, the SnO2 NPs/rGO‐1composite exhibits excellent reversible capacity and cycling stability (400 mA h g−1 at 1000 mA g−1 after 100 cycles for LIBs and 212 mA h g−1 at 100 mA g−1 after 100 cycles for SIBs). The simple, economical, and environmentally friendly synthetic route will be of great significance to the design of anode materials for LIBs and SIBs in the future.

Superhydrophobic SnO2 nanowire/graphene heterostructure-based ultraviolet detectors

As ultraviolet (UV) sensors are often employed in external environments, they should be able to function efficiently outdoors while remaining unaffected by liquids or changes in humidity. In this study, we developed a tin (IV) oxide nanowire (SnO2 NW)/graphene heterostructure-based UV detector that can accurately detect UV light without being affected by exposure to liquids. A (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) phosphonic acid (HDF–PA) passivation layer was self-assembled on an SnO2 NW/graphene heterostructure sensing channel to make its surface superhydrophobic (contact angle of ∼154°). This configuration prevents UV sensing distortion due to current leakage in case the sensor is exposed to various liquids. HDF–PA, which is less than 1.5 nm thick, slightly reduces UV transmission, rendering it a suitable passivation material to repel external liquids. In addition, the heterostructure of SnO2 NWs and graphene, as a UV sensing channel, can provide higher UV sensitivity than that of pristine graphene. The proposed method can be applied to fabricate stable, sensitive, and robust optical sensors that can withstand various environmental conditions.

Synthesis of Cu2CO3(OH)2/SnO2@GO composite as novel anode material for lithium ion battery application

Li-ion energy storage materials with high specific capacity and low cost have attracted much attention. Herein, a novel Cu2CO3(OH)2 composite modified with SnO2 nanowires and graphene oxide (GO) nanosheets (Cu2CO3(OH)2/SnO2@GO) termed as CC/SnO2@GO) for anode electrodes were synthesized by a solvothermal reaction. The expected compound are characterized by X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetry (TG) techniques. The electrochemical properties for Cu2CO3(OH)2/SnO2@GO are tested by battery testing system. The results show that highly reversible capacities of 928.5 mAh g−1 at 200 mA g−1 are obtained with excellent coulombic efficiency closed to 100% after 200 cycles. Consider of strategy of synergistic effects, CC/SnO2@GO shows a low charge/discharge voltage platform (0.5–1.0 V). This material may be promising as a new candidate for high-energy anode material in lithium ion batteries.

Incorporation of Reduced Graphene Oxides for Enhancing the Gas Sensing Characteristics

Incorporation of Reduced Graphene Oxides for Enhancing the Gas Sensing Characteristics

Zero-dimensional heterostructures: N-doped graphene dots/SnO2 for ultrasensitive and selective NO2 gas sensing at low temperatures

Facile synthesis of zero-dimensional heterostructures consisting of N-doped graphene quantum dots (N-GDs) and SnO2 nanoparticles is reported for the NO2 gas sensor with high sensitivity and excellent selectivity.

Free-Standing SnO2@rGO Anode via the Anti-solvent-assisted Precipitation for Superior Lithium Storage Performance.

Metal oxides have been attractive as high-capacity anode materials for lithium-ion batteries. However, oxide anodes encounter drastic volumetric changes during lithium ion storage through the conversion reaction and alloying/dealloying processes, leading to rapid capacity decay and poor cycling stability. Here, we report a free-standing SnO2@reduced graphene oxide (SnO2@rGO) composite anode, in which SnO2 nanoparticles are tightly wrapped within wrinkled rGO sheets. The SnO2@rGO sheet is assembled in high porosity via an anti-solvent-assisted precipitation of dispersed SnO2 nanoparticles and graphene oxide sheets in the distilled water, followed by the filtration and post-annealing processes. Significantly enhanced lithium storage performance has been obtained of the SnO2@rGO anode compared with the bare SnO2 anode material. A high charge capacity above 700 mAh g−1 can be achieved with a satisfying 95.6% retention after 50 cycles at a current density of 500 mA g−1, superior to reserved 126 mAh g−1 and a much lower 16.8% retention of the bare SnO2 anode. XRD pattern and HRTEM images of the cycled SnO2@rGO anode material verify the expected oxidation of Sn to SnO2 at the fully-charged state in the 50th cycle. In addition, FESEM and TEM images reveal the well-preserved free-standing structure after cycling, which accounts for high reversible capacity and excellent cycling stability of such a SnO2@rGO anode. This work provides a promising SnO2-based anode for high-capacity lithium-ion batteries, together with an effective fabrication adoptable to prepare different free-standing composite materials for device applications.

The realization of an ultrasensitive multifunctional sensor through the formation of Sn[sbnd]O[sbnd]C bonds and favorable electron transfer direction

The combination of reduced graphene oxide (rGO) and SnO2 quantum dots (QDs) exhibits excellent sensitivities to formaldehyde, ethanol, acetone and methanol. Among the prepared sensors, SnO2QDs/rGO (0.5 wt%) heterostructure sensors exhibit the highest sensitivity especially to formaldehyde at room temperatures (RT) and ethanol at 220 °C. And sensitivities change from 215 to 4450 toward 0.4–40 ppm formaldehyde at RT and 34.8–403.3 toward 1–1000 ppm ethanol at 220 °C. The high sensitivity is not only attributed to the reaction active center which provided by the heterojunctions between SnO2QDs and rGO, but also derived from effective electron transfer on the interface between SnO2QDs and rGO via SnOC bonds. In particular, for typical n-type semiconducting behavior, electrons transfer from rGO to SnO2QDs benefits gas sensitivity profoundly. The research of sensing mechanism and performance toward formaldehyde at room temperature and application as multi-functional gas sensors is crucial in practical application.

Multi-Layer Graphene/SnO2 Nanocomposites as Negative Electrode Materials for Lithium-Ion Batteries

Abstract We report the synthesis of SnO2/multi-layer graphene nanocomposites by an easy low temperature (60 °C) electroless plating route. An aqueous suspension containing Sn(BF4)2 with multi-layer graphene is reacted at 60 °C in an acidic environment for 1 h, and Na2S2O4 is used to reduce tin ion from Sn(BF4)2. After electroless plating, the presence of SnO2 particle (15–35 nm) attached to the multi-layer graphene is confirmed by transmission electron microscopy. Tin oxide (SnO2) can be used to modify multi-layer graphene via electroless plating process decorating with oxygen-containing functional groups. It is found that the electroless plating has enhanced the electrochemical performance of SnO2 and multi-layer graphene that shows reasonably good capacity (∼243 mAh g−1 after 50 charge/discharge cycles) and high Coulombic efficiency (∼78%).

Role of sensitizers in imparting the selective response of SnO2/RGO based nanohybrids towards H2S, NO2 and H2

Excellent electrical and sensing properties of reduced graphene oxide (RGO) and SnO2 have enabled fabrication of nanohybrid sensor with improved response characteristics. Nanohybrids of these two materials harnessing the advantages of the individual components thereby enables tailor made sensors for specific target gases. In the present work, using metal and metal oxide sensitizers, the response of the RGO nanohybrids was systematically tailored towards H2S, NO2 and H2 gases. Pristine SnO2/RGO nanohybrids demonstrated a highly sensitive and selective response towards H2S. It exhibited a sensor response of 3.7 towards 40 ppm of H2S at 200 °C. Incorporation of Pt and Pd into the nanohybrid matrix has resulted in an enhanced and selective response towards H2 and NO2, respectively. The maximum response of 124 and 49 were obtained towards 2 and 1.6% ofNO2 and H2, respectively. The lowest detection limits were 0.2%, 0.4 and 1 ppm for H2, NO2 and H2S, respectively.

Ferrocene as a Novel Additive to Enhance the Lithium-Ion Storage Capability of SnO2/Graphene Composite

Improving the reversibility of conversion reaction is a promising way to enhance the lithium-ion storage capability of SnO2-based anodes. Herein, we report ferrocene as a novel additive to improve the Li-ion storage performance of the SnO2/graphene (SnO2/G) composite. Through a simple mixing method, ferrocene can be uniformly dispersed into the SnO2/G electrode. It is found that the ferrocene additive can effectively suppress the agglomeration of Sn/SnO2 and retain the nanoscale Sn/Li2O interface. Furthermore, metallic Fe is formed from ferrocene in the discharge process and acts as a catalyst to promote the reversible conversion between Sn/Li2O and SnO2. As a result, the SnO2/G electrode with the addition of 10 wt % ferrocene (10%Fc-SnO2/G) exhibits a superior Li-ion storage performance. It displays a reversible capacity of up to 1084.5 mAh g-1 at 0.1 A g-1 after 150 cycles with a good rate capability (752 mAh g-1 at 1 A g-1). In addition, the 10%Fc-SnO2/G electrode can retain a capacity of 787.2 mAh g-1 at 0.5 A g-1 after 220 cycles. This work demonstrates the promising additive of ferrocene in enhancing the reversible capacity of SnO2-based anodes for lithium-ion batteries.

Synthesis of nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels and characterization of electrode materials

The macroscopic nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels were synthesized by one-step hydrothermal method using graphene oxide and SnCl2 as precursors and ammonia water as nitrogen source. The graphene oxides were reduced to graphene during the hydrothermal process at the same time SnCl2 was oxidized to SnO2 nanoparticles that were uniformly anchored onto the graphene sheets, resulting in the assembly of nitrogen-doped reduced graphene oxide/SnO2 composite hydrogels. The feed ratio of graphene oxide to SnCl2 played a key role in the formation of composite hydrogel. The unique structure and the synergistic effect between nitrogen-doped reduced graphene oxide and SnO2 in the composite architectures not only provided the large surface area but also facilitated the transportation of ion and electron through the three-dimensional network. Therefore, the nitrogen-doped reduced graphene oxide/SnO2 composite hydrogel exhibited an improved capacity and high cycling stability, suggesting the composite hydrogels could be promising candidates for energy storage.

Facile synthesis of SnO2-graphene composites employing nonthermal plasma and SnO2 nanoparticles-dispersed ethanol

The tin oxide (SnO2)-graphene composite was synthesized by the in-liquid plasma method using SnO2 nanoparticles (average diameter ~30 nm) dispersed ethanol as a precursor without providing external heat. As observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the SnO2 nanoparticles were distributed uniformly on flaky graphene sheets. The formation of SnO2 and high crystalline graphene was supported by the Raman analysis and x-ray diffraction (XRD) studies. A facile, low-cost method operating at atmospheric pressure based on the in-liquid plasma technology can be utilized to fabricate SnO2-graphene composite using minimum precursors for future applications such as gas sensing devices and fuel cells.

1D ultrafine SnO2 nanorods anchored on 3D graphene aerogels with hierarchical porous structures for high-performance lithium/sodium storage

SnO2 is considered as one of the most promising alternative anode materials for lithium ion batteries (LIBs) and sodium ion batteries (SIBs) due to high specific capacity, low discharge voltage plateau and environmental friendliness. In this work, 1D ultrafine SnO2 nanorods anchored on 3D graphene aerogel (SnO2 NRs/GA) composite is prepared through a simple reduction-induced self-assembly method in the solution of graphene oxide (GO), Vitamin C and SnO2 nanoparticles. Vitamin C plays an important role in the reduction of GO. The structural and morphological characterizations demonstrate that 1D ultrafine SnO2 nanorods are uniformly and tightly anchored on the surface of 3D graphene nanosheet aerogels. The unique 3D network structure as well as the synergistic effect between 3D graphene nanoshhet and 1D SnO2 nanorods endows the as-prepared SnO2 NRs/GA composite with the good electrochemical lithium/sodium storage performance. It delivers the high initial discharge capacity (1713 mA h g−1 at 0.1 A g−1 for LIBs and 539 mA h g−1 at 0.05 A g−1 for SIBs) and good cycle stability (869 mA h g−1 at 0.1 A g−1 after 50 cycles for LIBs and 232 mA h g−1 at 0.05 A g−1 after 100 cycles for SIBs). Moreover, the SnO2 NRs/GA composite exhibits excellent cycle stability for SIBs with a high reversible capacity of 96 mA h g−1 at as high as 1 A g−1 for 500 cycles. This work provides a simple method to fabricate the electro-active materials-graphene aerogel composites for high-performance LIBs and SIBs.