SnO2 Particles Research Articles

Arc erosion behaviors of the densified Ag-SnO2 contact materials containing sub-micron and nano In2O3 additives

The effects of In2O3 additive size on the physical properties and arc erosion behaviors of the densified Ag-SnO2 materials were investigated. Arc resistance mechanism was analyzed based on the microscopic morphology characterization. Results revealed that the physical properties of the Ag-SnO2(In2O3) materials were significantly improved after densification. Relative density and electrical conductivity of the materials reached above 99.5% and 71%IACS, respectively. The densified Ag-SnO2 material containing sub-micron In2O3 showed the low and stable break arc energy. The mass loss of the cathode was dramatically decreased by 65.4%. Importantly, the generation of pores and micro-cracks on the surface of electrodes were significantly restrained and the contact resistance became more stable. By comparison, the nano In2O3 additive less than 100 nm effectively suppressed not only the splash of molten Ag on the surface of cathode but also the aggregation of SnO2 particles on anode. The arc erosion products were obviously decreased, resulting in an enhancement of arc-erosion resistance of Ag-SnO2(nano In2O3) materials. Compared with that without additive, the mass loss of the Ag-SnO2 material which contains nano In2O3 obviously decreased from 2.3 to 1.4 mg. The optimal mass fraction of nano In2O3 in the Ag-SnO2 contact materials was 1 wt%.

A Novel Palm Sugar-Mediated Hydrothermal Synthesis of Spherical Tin Oxide for Enhanced SO2 Gas Detection

Sulfur dioxide (SO2), a hazardous gas resulting from combustion and natural reactions, poses environmental and health risks. This study presents a novel approach to synthesize tin oxide (SnO2) using palm sugar-mediated hydrothermal methods for enhanced SO2 gas sensing. The simplicity and cost-effectiveness of the method are highlighted, addressing challenges posed by complex and resource-intensive conventional methods. Spherical SnO2 particles were successfully synthesized and characterized using SEM and XRD techniques. From the SEM image, it was known that SnO2 has spherical morphologies and is expected to agglomerate after being calcined. XRD analysis shows that SnO2 has a rutile tetragonal phase structure. The synthesized SnO2 demonstrated favorable gas sensing properties when exposed to SO2, exhibiting elevated response at increased temperatures and a linear relationship between response and gas concentration. The results indicate the potential of this method for effective and efficient SO2 detection.

SnO-SnO<sub>2</sub> Nanocomposites Based pn Diode: <i>In Situ</i> Synthesis, Characterization and Fabrication of Device for pn Diode Applicability

We report on an approach for the in-situ synthesis (chemical method based) of SnO-SnO2 nanocomposites followed by characterisation (including morphological, chemical, structural and optical) and investigation of the electrical properties of the nanocomposites with reference to the as-synthesized SnO2 nanoparticles. Compared to spherical SnO2 particles, the SnO phase is found existing in the form of sheet like morphology. It has been found that through controlling of the Sn:OH precursor ratio is effective for the achievement of SnO phase. Compared to the pristine SnO2 nanoparticles, the current-voltage (I-V) characteristics of the nanocomposites show the p-n junction characteristics. The observation of rectification ratio 2.05 indicates the excellent rectifying property of the nanocomposites due to the presence of p-type SnO phase. Further, exploration of the I-V characteristics has revealed the dominance of space-charge limited current transport mechanism for the nanocomposites sample. The lattice defects are discovered to be the cause of the transport mechanism in the nanocomposites sample.

Regulation of domain wall motion in PZT-based ceramics through the introduction of local stress fields

At present, a big challenge exists yet in the piezoelectric ceramic material that high piezoelectric performance and low losses (large Qm and low tanδ) are difficult to achieve concurrently due to the effects of domain switching and domain wall motion on electromechanical properties. In this work, by introducing secondary-phase particles (SnO2 particles) into the hard PZT matrix, we successfully build local stress fields in the ceramic. These local stress fields not only pin the domain and domain wall but also diminish the domain size and increase the domain wall density. The former is in favor of reducing the losses, while the latter is beneficial to promoting the piezoelectric properties. Thus, the optimized piezoelectric properties and losses in the ceramic can be obtained simultaneously. The results show that in the PZT/0.3 wt%SnO2 composite, the mechanical quality factor reaches 2800 and the dielectric loss is only 0.4 %, which are superior to the hard PZT matrix. Meanwhile, the composite ceramic has a high piezoelectric constant of 390 pC/N. These excellent properties will push the development of next-generation high-power electromechanical devices.

Highly responsive room-temperature NO2 sensor based on oxygen vacancies-rich SnO2-RGO hybrids

The development of graphene-based room-temperature NO2 sensors with high sensitivity remains a challenge. Herein, a wet-chemical etching strategy is investigated to introduce oxygen vacancies onto SnO2-RGO using ethanolamine (EA) as etching agent, thereby improving the NO2 response of room-temperature NO2 sensors. The oxygen vacancies-rich SnO2-RGO (EA-SnO2-RGO) is simply prepared by stirring SnO2-RGO in EA solution at room temperature, which not only decreases the size of SnO2 particles in EA-SnO2-RGO, but also introduces additional oxygen vacancies onto SnO2 particles surface. Notably, EA-SnO2-RGO sensor presents a high response value of 5.8 (1 ppm NO2) at room temperature, that is 2.1-fold larger than the response value for SnO2-RGO. Simultaneously, EA-SnO2-RGO sensor also demonstrated short response time (95 s) and good selectivity, indicating huge potential applications for room-temperature NO2 detection. This study provides new strategy to fabricate high-performance gas sensors operated at room-temperature.

Sensing analysis of polyaniline – stannous chloride pentahydrate composite of CO2 gas sensors

ABSTRACT In this experimental work, the composite of polyaniline-stannous chloride pentahydrate (PSCL) was synthesized at room temperature through polymerization using FeCl3 as an oxidant. The sensing was carried out at room temperature for a 150 ppm concentration of CO2 gas. The PSCL composite was coated on a glass substrate. The PSCL composite was characterized by XRD, FTIR, and Impedance spectroscopy analysis. XRD and FTIR confirm the formation of SnO2 particles in composites. The ideal capacitor will have phase angle at −90° which is shown by PSCL (10% and 20%) composites which indicate that they have lower ionic permeability and show there insulating properties. Whereas composites PSCL (5% and 15%) at low frequency show high ionic permeability, as they have phase angle near to −45° which makes them poor insulators. The response and recovery times of composites are [130 s, 31 s], [142 s, 556 s], [134 s, 98 s], and [113 s, 90 s] for PSCL 5%, 10%, 15%, and 20%. PSCL 15% shows better sensitivity toward CO2 gas at room temperature. PSCL composites show complete reproducibility. The migration of electron between the p-n junction formed in the composite and concentration of SnCL4. 5 H2O in the PSCL composite make it sensitive toward exposed CO2 gas.

Size-Dependent Response of Hydrothermally Grown SnO2 for a High-Performance NO2 Sensor and the Impact of Oxygen.

A NO2 sensor with a detection limit down to the ppb level based on pristine SnO2 has been developed through a facile poly(acrylic acid)-mediated hydrothermal method. SnO2 particles of solid microsphere, hollow microsphere, and nanosphere morphologies were synthesized, with respective constitutional crystallite of size ∼2 μm in length and 10-20 nm and ∼7 nm in diameter. All sensors show great selectivity to NO2. The hollow microsphere sensor exhibits the best performance, with medium specific surface area (SSA), followed by the nanosphere sensor with the largest SSA. This is attributed to the superposition of two opposite effects on sensor response with increased SSA: more adsorption sites and fewer electrons to be taken out with overly small crystallite that may reach complete depletion. O2 is found to speed up the response and recovery times but reduce the response because O adsorbates facilitate the adsorption/desorption of NO2 thermodynamically, and the two oxidizing gases compete in harvesting electrons from SnO2. The adverse effect of humidity can be minimized by operating the sensor at 110 °C. The response of the hollow microsphere sensor to 50 ppb of NO2 is 8.8 (Rg/Ra) at room temperature, and it increases to 15.1 at 110 °C. These findings are useful for developing other oxidizing gas semiconductor sensors.

Embedding Pd into SnO2 drastically enhances gas sensing.

Combustion aerosol processes can uniquely embed noble metals into semiconducting particles. Here, monocrystalline SnO2 particles embedded with Pd and/or PdOx were made by flame spray pyrolysis (FSP) of appropriate precursors through microexplosions by droplet-to-particle conversion as the crystal size was proportional to the cube root of precursor solution concentration, C. These particles were air-annealed and leached with nitric acid for removal of metallic Pd from their surface. The SnO2 crystal size varied from 11 to 24 nm and was in close agreement with the primary particle size determined by nitrogen adsorption. The embedded fraction of Pd ranged from about 30 to 80% of the nominal Pd-content. This was achieved by judiciously varying the C, Pd content and the ratio of precursor solution to dispersion oxygen flowrates during FSP. The response of sensors made by doctor blading films of such particles to 1 ppm of acetone and CO was evaluated at 350 °C and 50% relative humidity. Embedding Pd/PdOx into SnO2 significantly increased the sensor response: 2-6 times over that of pure or conventionally-made Pd-containing SnO2 sensors at low nominal Pd-contents (0.2 mol%). For higher ones (i.e. 1 mol% Pd), the sensor response was enhanced by up to two orders of magnitude. This is attributed to Pd atoms in the SnO2 lattice near the particle surface and/or Pd/PdOx clusters acting as nanoelectrodes into SnO2 films and altering their transducing properties as shown by high resolution electron microscopy, XPS and baseline resistance measurements of pure and Pd-embedded SnO2 sensing films.

A Comparative Study of Coprecipitation and Solvothermal Techniques for Synthesizing Pure and Cu‐Doped SnO2 Nanoparticles

Tin oxide (SnO2), with its low resistivity properties and high transparency in the visible spectrum, makes it an attractive electron transfer layer (ETL) for use in perovskite solar cells. Here, we use two techniques, coprecipitation and solvothermal, to synthesize pure and 4% copper‐doped SnO2. The X‐ray diffraction patterns revealed that the films synthesized using both methods have a crystalline structure with a tetragonal arrangement. Furthermore, the lack of any secondary peaks indicated the absence of mixed tin oxide (Sn2O4) or copper oxide (CuO) components. Additionally, it demonstrated that adding a 4% Cu doping concentration reduced the crystal size in both methods. The optical results indicate adequate transmission in the central range of the visible spectrum. Calculations were performed to find the energy gap of pure SnO2 in both techniques to be 3.85 eV and 4.17 eV, respectively. When we doped SnO2 with 4% Cu, this band gap energy decreased to 3.75 eV and 3.9 eV. Furthermore, with 4% Cu doping, the particle size decreases, as demonstrated by FESEM. The EDX spectroscopy images revealed that the synthesized nanoparticles consisted of copper, oxygen, and tin. The analysis of functional groups using Fourier transform infrared (FTIR) spectra and the roughness analysis using AFM images showed a decrease in roughness from 46.1 nm to 12.3 nm in doped samples prepared by solvothermal synthesis, compared to those synthesized by the coprecipitation technique from 4.7 nm to 0.3 nm. We discovered that Cu plays an essential role in reducing nanocrystalline SnO2 particle sizes. In addition, the solvothermal technique is more impressive than coprecipitation in the synthesis of tin oxide nanostructure.

Effect of SnO2 particle size on gas-sensing performance for ppb-level NO2 at room temperature under UV light

Effect of SnO2 particle size on gas-sensing performance for ppb-level NO2 at room temperature under UV light

The Impact of Mesopores of SnO2 Catalyst Support on the Performance of Polymer Electrolyte Fuel Cells

Recently, the focus of future polymer electrolyte fuel cell (PEFC) application for automobiles has shifted from the class of passenger light-duty vehicles (LDVs) to that of heavy-duty vehicles (HDVs). The total operating time in the lifetime of HDVs is much longer than that of LDVs. Thus, durability is becoming more and more important for the cell components including the catalyst materials, and the compatibility between initial performance and durability at a high level is desired. Employing mesoporous carbons as catalyst supports is a promising option to enhance the initial performance [1]. In the catalyst layer of a PEFC with mesoporous carbon support, Pt-based catalyst nanoparticles deposited inside the mesopores are not directly covered by ionomer. As a result, a catalyst poisoning by sulfonic acid groups of the ionomer is hindered and a high catalytic activity is obtained. In addition, a high oxygen transport resistance thorough Pt/ionomer interfaces [2] can be mitigated by employing mesoporous carbon support. Nonetheless, from the viewpoint of thermodynamics, carbon support can oxidatively degrade during the long-term operation. Tin oxide (SnO2) is one of the promising candidates for substituting the carbon support because of its high electrochemical stability at high potentials [3]. However, to our best knowledge, the mitigation of the ionomer adsorption on the Pt surface by using mesoporous SnO2 support has not been studied in previous works. In this study, we synthesized mesoporous SnO2 supports and investigated the impact of the mesopore on the performance of the PEFC. Connected mesoporous Sb-doped SnO2 particles (CMSbTOs) were synthesized by using a mesoporous carbon as a template (Figure (a)). The size of the mesopore was successfully controlled in the range of 4 – 10 nm by adjusting the carbon template structure and calcination temperature (Figure (b)). The BET surface area and conductivity of the CMSbTOs were in the ranges of 90 – 210 m2 g-1 and ca. 10-2 S cm-1, respectively. Pt nanoparticles were deposited on the CMSbTOs via a colloidal method to obtain Pt/CMSbTO catalyst (Pt loading of 20 wt.%). It was confirmed that the Pt nanoparticles were located both on the outer surface and inside the mesopores of the CMSbTOs by scanning transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) analysis. A membrane electrode assembly (MEA) was fabricated by using a Pt/CMSbTO catalyst for the cathode catalyst layer and single cell tests were performed under dried (30%RH, 82 °C) and highly humidified (80%RH, 60 °C) conditions. In addition, a homemade Pt/Sb-SnO2 catalyst with solid-core SnO2 support and a commercial Pt/Vulcan catalyst (TEC10V30E, TKK) were also tested for comparison. Under the dried conditions, the Pt/CMSbTO catalyst showed a better I-V performance than the Pt/Sb-SnO2 (solid) catalyst and Pt/Vulcan catalyst (Figure (c)). The oxygen reduction reaction (ORR) activity of the Pt/CMSbTO catalyst at 0.84 V was higher than that of the Pt/Sb-SnO2 (solid) and Pt/Vulcan catalysts. This result suggests that catalyst poisoning by the ionomer is mitigated when the mesoporous SnO2 support is employed. Moreover, the local oxygen transport resistance (oxygen transport resistance that is independent of the total gas pressure) of the Pt/CMSbTO catalyst was lower than that of the Pt/Sb-SnO2 (solid) and Pt/Vulcan catalysts, probably because of a decrease in the oxygen transport resistance due to Pt/ionomer interfaces. In contrast, under the highly humidified conditions, the I-V performance of the Pt/CMSbTO catalyst was comparable to that of the Pt/Sb-SnO2 (solid) catalyst and slightly lower than that of the Pt/Vulcan catalyst (Figure (d)). This result can be ascribed to floodings inside the mesopores of the CMSbTO support. Accelerated stress tests (repeated potential steps between 1.0 – 1.5 V under 100%RH, 80 °C) were also performed to confirm the electrochemical stability of the Pt/CMSbTO catalyst at high potentials. The Pt/CMSbTO catalyst showed a much higher retention rate of the electrochemical Pt surface area (ECSA) than the Pt/Vulcan catalyst as expected. More details, including the effect of the pore size of the CMSbTO support on the initial performance, will be discussed in the presentation.

Fabrication of stable and selective non‐noble metal catalysts for selective alkyne hydrogenation

AbstractModification of Ni/Al2O3 catalysts with Sn is appealing for tuning catalyst activity and selectivity for hydrogenation reactions. However, a strong interaction between the Al2O3 and Sn ions can lead to problems when a traditional impregnation strategy is employed. For example, tin aluminate complexes can form and uneven distribution of the metals can occur. In this work, a support coordination induction strategy is developed, in which the use of a rod‐shaped Al2O3 with a high number penta‐coordinated Al3+ surface species prepared from a rotating liquid film reactor was used. The unsaturated Al3+ coordination sites on this support induce the formation of a stable and uniform Ni‐Sn intermetallic phase without the appearance of either monometallic Ni or SnO2 particles. This uniform Ni‐Sn intermetallic phase was then shown to be responsible for enhanced activity, selectivity, and stability for alkyne hydrogenation relative to samples which lacked the same level of Ni‐Sn uniformity.

Tunable composition of Sn/SnO2@C composites for lithium-ion batteries

Sn-based anodes are the most viable option for lithium-ion batteries (LIBs), but their widespread implementation is hindered by suboptimal kinetics properties and structural failures. Herein, an effective anode material has been synthesized for LIBs, consisting of a carbon-encapsulated matrix with particles of Sn and SnO2 (Sn/SnO2@C) composites. The synergistic effect between SnO2 and Sn significantly improves both mechanical stability and kinetic properties. Additionally, the presence of a carbon matrix enhanced electronic conductivity as well as effectively mitigating volume expansion during cycling. As expected, the Sn/SnO2@C electrode realizes decent cycle stability and impressive rate performance. The work offers a promising approach for enhancing the performance of tin-carbon composites.

Narrowband photoluminescence of Tin-Vacancy colour centres inSn-doped chemical vapour deposition diamond microcrystals.

Tin-Vacancy (Sn-V) colour centres in diamond have a spin coherence time in the millisecond range at temperatures of 2 K, so they are promising to be used in diamond-based quantum optical devices. However, the incorporation of large Sn atoms into a dense diamond lattice is a non-trivial problem. The objective of our work is to use microwave plasma-assisted chemical vapour deposition (CVD) to grow Sn-doped diamond with submicron SnO2 particles as a solid-state source of impurity. Well-faceted diamond microcrystals with sizes of afewmicrometres were formed on AlN substrates. The photoluminescence (PL) signal with zero-phonon line (ZPL) peak for Sn-V centre at ≈620 nm was measured at room temperature (RT) and at 7 K. The peak width (full width at half-maximum) was measured to be 1.1-1.7 nm at RT and ≈0.05 nm at 7 K. The observed variations of ZPL shape and position, in particular, narrowing of PL peak at RT and formation of single-line fine structure at low-T, are attributed to strain in the crystallites. The diamond doping with Sn via CVD process offers a new route to from Sn-V colour centre in the bulk of the diamond crystallites. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'.

Conducting polymer wrapped SnO2/RGO nanocomposite: An efficient high-performance supercapacitor material

This study describes a ternary poly (3,4-ethylenedioxythiophene)-poly-(styrenesulfonate) (PEDOT:PSS)-wrapped tin oxide/reduced graphene oxide (SnO2/RGO/PEDOT: PSS) (SGP) nanocomposite electrode as a supercapacitor electrode. The properties of the SGP nanocomposites were studied using various characterization techniques such as X-ray Diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), Raman spectroscopy, and electrochemical impedance spectroscopy. The XRD results demonstrated the reduction of graphene oxide during the synthesis. TEM analysis confirmed the presence of PEDOT: PSS and graphene layers adorned with minuscule SnO2 particles. Standard three-electrode geometry was used to investigate the electrochemical properties of the samples. For comparison, a two-electrode system was used to investigate the electrochemical properties. The as-prepared SGP nanocomposite electrode exhibited specific capacitance of 252.0 F/g and 124 F/g at a scan rate of 1 mV/s for the three-electrode and two-electrode systems, respectively. Furthermore, the electrode retained approximately 97.8 % of its capacitance even after 5000 cycles. However, the SGP electrode when operated to wide voltage window -0.6 V to +0.6 V exhibited the maximum specific capacitance of 285.0 F/g at scan rate 1 mV/sec and shows 114 % enhancement in the capacitance retention after the 5000 cycles at current density of 10 A/g which gives a protocol for future energy storage device application with high operating voltage. The SGP-based supercapacitor exhibited a high energy density (17.7 Wh kg −1) and power density (1220 W kg −1).

Sb/SnO@C composite prepared by electrospinning for high performance sodium ion battery anodes

The development of high-performance anode material for sodium-ion batteries remains a challenge because of their low capacity, which limits their commercial application. Compared with carbon-based materials, metallic Sb and SnO-based anodes have received extensive attention because of their high theoretical specific capacity and safe working potential. The main problem faced is the serious volume expansion during charging and discharging, leading to irreversible loss of capacity and poor cycle life. In this paper, Sb/SnO@C composite material with adjustable ratio of Sb/SnO was prepared via electrospinning by encapsulating Sb and SnO particles in lantern-like carbon nanocages which connected through the nanofibers. The unique structure can not only effectively mitigate the volume changes during the cycle, but also provide multiple effective paths for ion and electron transport. The kinetic analysis is further performed with the assist of CV and EIS. The results show that the prepared composite can provide impressive Na+ ions storage and transport performance, and can still deliver a reversible charging capacity of 413mAhg−1 after 200 cycles at a current density of 50mAg−1, with a capacity retention ratio of 84%. This work provides a new strategy for the development of sodium ion batteries with high capacity and stable cycle performance.

Solar light induced photocatalytic degradation of textile dyes using solvothermally synthesized SnO2 impregnated pumice stone

In this study, a facile solvothermal route was utilized to immobilize SnO2 on the surface of pumice stone and used as a photocatalyst to remove methyl orange (MO) and crystal violet (CV). Based on the SEM findings, the SnO2 particles were successfully immobilized on the surface of the pumice without aggregation. Also, the immobilization of SnO2 was identified using XRD, EDS, XRF and FTIR analysis. The UV–vis spectroscopy measurement revealed the energy bandgap of pristine pumice and SnO2/pumice composite was found to be 2.71 and 2.55 eV, respectively. The BET surface area of SnO2/pumice is about 29.08 m2 g−1, with pore volume and pore radius of up to 0.045 cm3 g−1 and 30.97 Ả, respectively. The photocatalytic activity of SnO2/pumice under sunlight irradiation shows the degradation of MO and CV by about 85 and 70% within 40 and 60 min, respectively. Moreover, the radical scavengers test discovered that h+ and OH ̇ radicals play a crucial role, whereas · O2 − radicals also exhibited a minor role in the degradation process. In addition, the XRD, FTIR, EDX and XRF analysis of the fresh and used SnO2/pumice sample was carried out to detect a minimal change in sample peaks even after the photocatalytic experiment. As a future aspect, after SnO2/pumice reusability, it can be again reused as a bare substrate in the same synthesis process.

Microwave-Assisted Synthesis of Pt/SnO2 for the Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol.

In this study, we present a new approach for the synthesis of Pt/SnO2 catalysts using microwave radiation. Pt(IV) and Sn(IV) inorganic precursors (H2PtCl6 and SnCl4) and ammonia were used, which allowed the controlled formation of platinum particles on the anisotropic SnO2 support. The synthesized Pt/SnO2 samples are mesoporous and exhibit a reversible physisorption isotherm of type IV. The XRD patterns confirmed the presence of platinum maxima in all Pt/SnO2 samples. The Williamson-Hall diagram showed SnO2 anisotropy with crystallite sizes of ~10 nm along the c-axis (< 00l >) and ~5 nm along the a-axis (< h00 >). SEM analysis revealed anisotropic, urchin-like SnO2 particles. XPS results indicated relatively low average oxidation states of platinum, close to Pt metal. 119Sn Mössbauer spectroscopy indicated electronic interactions between Pt and SnO2 particles. The synthesized samples were used for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of excess NaBH4. The catalytic activity of the Pt/SnO2 samples for the reduction of 4-NP to 4-AP was optimized by varying the synthesis parameters and Pt loading. The optimal platinum loading for the reduction of 4-NP to 4-AP on the anisotropic SnO2 support is 5 mol% with an apparent rate constant k = 0.59 × 10-2 s-1. The Pt/SnO2 sample showed exceptional reusability and retained an efficiency of 81.4% after ten cycles.

Superior lithium storage performance of SnO2–modified Co3O4 microflowers self–assembled with porous nanosheets as anode materials in Li–ion batteries

SnO2–modified Co3O4 microflowers self–assembled with porous nanosheets are prepared with the help of solvothermal methods and annealing treatment without using any templates, and ultra–small SnO2 particles are dispersed on the surface of the Co3O4 nanosheets. The structures and physical properties of the as–synthesized samples are characterized by XRD, FESEM, HRTEM, EDS, element mapping, ICP–AES, XPS and N2 adsorption/desorption measurement. According to the N2 adsorption–desorption isotherm curves, the samples show hierarchically porous structures, and SnO2–modified Co3O4 microflowers have a higher surface area (19.5 m2 g–1 for Co3O4; 30.5 m2 g–1 for SnO2–modified Co3O4). As anode materials in Li–ion batteries, compared with bare Co3O4 microflowers, the SnO2–modified Co3O4 sample delivers higher specific capacity, better rate capability and superior cyclic stability. The discharge capacity of the SnO2–modified Co3O4 sample can reach 767.5 mAh g–1 at 200 mA g–1 after 100 cycles. For even at 3.0 A g–1, the reversible capacity of the composite can still reach 438.8 mAh g–1 after 1000 cycles.

Study on photocatalytic, electric, and sensing behavior of Co- and Ag-codoped tin dioxide (SnO2) nano particles

In the current work, the role of Co and Ag co-doping on the electric, optical, and sensing performance of tin dioxide nano particles was investigated. Hydrothermally (co-)precipitation of the dopants was utilized to fabricate pure SnO2 and Sn0.96-xCo0.04AgxO2 (x = 0, 0.02, 0.04) nanoparticles. The crystal structure and microstructure of SnO2 particles was almost unchanged although Co-Ag co-doping reduced particle size from 51.8 nm to 41.6 nm and the unit cell dimensions changed. Overall, Co and Ag resulted in significant rise in oxygen vacancy of SnO2 so that defects compensate unbalanced electron charge induced by dopants. It was also figured out that Co-Ag co-doping improved the conductivity of dioxide at low and high temperatures. Doping Led to decrement in the band gap energy of tin dioxide from 3.66 eV to 3.07 eV, which shows improved optical properties of the compound. Study on photodegradation activity of SnO2 showed up to 97 % enhancement due to Co-Ag co-doping. Finally, the sensor response of the compound revealed that the response intensity of tin dioxide increased significantly when 4 wt % Co and 2 wt % Ag are doped into it.