Surface Of SnO2 Nanoparticles Research Articles

Tetragonal SnO2 Nanoparticles: An Efficient Photocatalyst for the Degradation of Hazardous Ionic Dyes

AbstractAn elegant approach was made to synthesize tetragonal shape SnO2 nanoparticles using solution combustion method and subjected to various characterization (X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV‐Vis diffuse reflectance spectroscopy (UV‐DRS), Photoluminescence (PL) spectroscopy, Raman spectra, thermogravimetric analysis (TGA), differential thermal analysis (DTA), X‐ray photoelectron spectrometer (XPS), N2 adsorption‐desorption isotherms (BET), liquid chromatography with mass spectrometry (LCMS). Dynamic light scattering (DLS) and Zeta potential (ZP), field emission scanning electron microscopy (FESEM), energy dispersive X‐rays analysis (EDAX), and High‐resolution transmission electron microscopy (HRTEM)). Further, the as‐synthesized SnO2 nanoparticles were used for the degradation study of hazardous ionic dyes like cationic dye Malachite green (MG) and anionic dye Rose Bengal (RB), as well as its binary mixture (MG+RB) under the sunlight. Overall, it was observed that MG and RB degraded 100 % (80 min) and 99 % (90 min), while the mixture of (MG+RB) showed 97.5 % (140 min), respectively. Overall study shows that the degradation rate of MG in a mixture of both the dyes was higher than RB due to a positively charged surface. The time taken for degradation MG was 10 min less than that of RB. The fast degradation of MG was due to the cationic nature having a positive charge over the surface with the negatively charged surface of SnO2 nanoparticles, which is entirely different in the case of anionic dye RB.

Thermal activation of Pd/CeO2-SnO2 catalysts for low-temperature CO oxidation

In this work, the counter precipitation method was used to synthesise Pd/CeO2-SnO2 catalysts, which possess excellent low-temperature activity and high thermal stability. It was revealed that calcination of Pd/CeO2-SnO2 catalysts at 800−1000 °C induces significant growth of catalytic activity in CO oxidation at T<150 °C. This effect of thermal activation for Pd/CeO2-SnO2 catalysts was enhanced when water was admitted to the reaction mixture. In the presence of water the T50 value for the Pd/CeO2-SnO2 catalyst calcined at 900 °C becomes 45 °C lower than for the Pd/CeO2 catalyst. It was found that calcination of the catalysts at T<600 °C leads to the formation of solid solutions based on the fluorite and rutile structures. As the calcination temperature is raised above 600 °C, the solid solutions decompose with formation of catalytically active PdxCe1-xO2-δdispersed phase on the surface of SnO2 nanoparticles. The formed nanoheterogeneous structure provides both high thermal stability and high water resistance of Pd/CeO2-SnO2 catalysts.

L-glycine-assisted synthesis of SnO2/Pd nanoparticles and their application in detection of biodeteriorating fungi

The presence of certain volatile organic compounds is used for the detection of fungi in the indoor environments. The synthesis of SnO2/Pd nanoparticles (NPs) was performed via the reduction of Pd2+ in the presence of l-glycine. The XRD and EDX results confirmed the presence of palladium on the surface of SnO2 NPs. The sensing properties of SnO2/Pd and SnO2 NPs towards the detection of 1-octen-3-ol were analyzed by a static process. The SnO2/Pd and SnO2 NPs fabricated sensors gave a response of 46.7% and 24.2%, respectively, for 700 ppm target gas at 250 °C. The estimated limit of detection and limit of quantification of the fabricated SnO2/Pd sensor at 250 °C in the linear segments are 20.94 ppm and 69.79 ppm, respectively. These results demonstrated that the synthesis of SnO2/Pd NPs in the presence of l-glycine as a reducing agent has potential applications in the detection of fungal biodeterioration in infected materials at the early stages of infection.

Nanoporous network SnO2 constructed with ultra-small nanoparticles for methane gas sensor

Monitoring the concentration of methane (CH4) can effectively protect the environment from the damage of methane emission. The high sensing performances of methane gas sensor still remain a considerable challenge. Herein, to solve problems mentioned above, nanoporous network SnO2 (NN-SnO2) construct with ultra-small nanoparticles, which exhibits excellent gas-sensing performances for methane, are successfully synthesized via a weak acid glucose-assisted hydrothermal synthesis. The NN-SnO2 displays three particular particle morphologies: roundness, oval and polygon, with an average particle size of ~ 9 nm. When evaluated as a sensing material for methane, the NN-SnO2 sensor exhibits ultra-high response (Ra/Rg = 9.80), fast response/recovery times (τres/τrecov= 1 s/3 s) toward 3000 ppm methane at a operating temperature of 420 °C, which are far superior to the vast majority methane semiconducting sensors, and more importantly, it has barely been reported that the sensor based on NN-SnO2 presented such excellent gas-sensing performances for methane. The outstanding response of the NN-SnO2 for methane gas is derived from the unique mesopores nature and small particles sizes of the as-synthesized NN-SnO2, and the charge transfer between the surface of SnO2 nanoparticles and methane gas molecules.

Physisorption of Oxygen in SnO2Nanoparticles for Perovskite Solar Cells

Although SnO2 is widely used in perovskite solar cells (PSCs) as the electron transport layer, there is still a need for a detailed investigation regarding the impact of physisorption on the performance of PSCs. Here, we report the role of physisorption of oxygen species from the ambient atmosphere in the oxidation states and defective oxides at the surface of SnO2 nanoparticles for the performance of PSCs. The SnO2 nanoparticle's thin film shows a higher oxidation state (Sn–O) and lower charge trap sites at an annealing temperature of 100 °C, and the SnO2 film based PSCs yield an efficiency of 18.04%. The annealing process results in the gradual desorption of physically adsorbed oxygen species. Therefore, the annealing process of SnO2 nanoparticle thin films in atmosphere is the key factor to control the oxidation states and defective oxides at the surface of SnO2 nanoparticle thin films.

Zinc Oxide Coated Tin Oxide Nanofibers for Improved Selective Acetone Sensing

Three-dimensional hierarchical SnO2/ZnO hetero-nanofibers were fabricated by the electrospinning method followed with a low-temperature water bath treatment. These hierarchical hollow SnO2 nanofibers were assembled by the SnO2 nanoparticles through the electrospinning process and then the ZnO nanorods were grown vertically on the surface of SnO2 nanoparticles, forming the 3D nanostructure. The synthesized hollow SnO2/ZnO heterojunctions nanofibers were further employed to be a gas-sensing material for detection of volatile organic compound (VOC) species such as acetone vapor, which is proposed as a gas biomarker for diabetes. It shows that the heterojunction nanofibers-based sensor exhibited excellent sensing properties to acetone vapor. The sensor shows a good selectivity to acetone in the interfering gases of ethanol, ammonia, formaldehyde, toluene, and methanol. The enhanced sensing performance may be due to the fact that n-n 3D heterojunctions, existing at the interface between ZnO nanorods and SnO2 particles in the SnO2/ZnO nanocomposites, could prompt significant changes in potential barrier height when exposed to acetone vapor, and gas-sensing mechanisms were analyzed and explained by Schottky barrier changes in SnO2/ZnO 3D hetero-nanofibers.

The effect of Ni doping concentration on the gas sensing properties of Ni doped SnO2

The Ni doped SnO2 has been prepared by two-step hydrothermal treatment and calcination, and characterized by XRD, TEM and Brunauer Emmett Teller N2 adsorption–desorption analysis. The results exhibit the Ni doped SnO2 is heterostructure composed of Ni-SnO2 on the surface of SnO2 nanoparticles, which are polycrystalline tetragonal with high specific surface area and average grain size of about 10nm. The sensors based on Ni doped SnO2 show very good gas sensing properties at low working temperature. The gas sensing properties of the Ni doped SnO2 are improved with low Ni-doping concentration (2–4mol%), but further increase of Ni-doping concentration results in deteriorated response by low conductivity. The sensor based on 2mol% Ni doped SnO2 and the sensor based on 4mol% Ni doped SnO2 show ultrahigh responses to n-butanol and formaldehyde, respectively, with good selectivity. These sensors could be promising candidates for selective detection of n-butanol and formaldehyde.

Facile Synthesis and Acetone Sensing Performance of Hierarchical SnO2 Hollow Microspheres with Controllable Size and Shell Thickness

A facile method to prepare SnO2 hollow microspheres has been developed by using SiO2 microspheres as template and Na2SnO3 as tin resource. The obtained SnO2 hollow microspheres were characterized by X-ray diffraction, scanning electron microscopy, high resolution and transmission electron microscopy, and Brunauer–Emmett–Teller analysis, and their sensing performance was also investigated. It was found that the diameter of SnO2 hollow microspheres can be easily controlled in the range of 200–700 nm, and the shell thickness can be tuned from 7.65 to 30.33 nm. The sensing tests showed that SnO2 hollow microspheres not only have high sensing response and excellent selectivity to acetone, but also exhibit low operating temperature and rapid response and recovery due to the small crystal size and thin shell structure of the hollow microspheres, which facilitate the adsorption, diffusion, and reaction of gases on the surface of SnO2 nanoparticles. Therefore, the SnO2 hollow microsphere is a promising material fo...

Chemical anchoring of aminobenzoate onto the surface of SnO2 nanoparticles for synthesis of polyaniline/SnO2 composite

In order to increase the conjunction between PANI and SnO2, an efficient method was proposed to synthesize polyaniline/aminobenzoate/tin dioxide composite (PANI–AB–SnO2) with tight junction structure via grafting PANI onto SnO2 nanoparticles modified with AB, in which AB was chemically anchored onto the surface of SnO2 nanoparticles. Characterization of structure and morphology of the composite indicated that COOH group of AB molecule could coordinate to Sn (IV) on the surface of SnO2 to form a bidentate bridging compound, and proved that the prepared composite existed stronger interaction force between PANI and SnO2 nanoparticles. Electrochemical property measurements showed that the composite had improved properties, and its specific capacitance was up to 259.5Fg−1 at a current density of 5mAcm−2, ca. 47.8% higher than that of PANI–SnO2 (175.5Fg−1) synthesized in the similar condition. In addition, it also showed a good electrochemical stability.

The roles of various Ni species over SnO2 in enhancing the photocatalytic properties for hydrogen generation under visible light irradiation

The photocatalysts containing various nickel species were successfully fabricated via loading Ni(OH)2 and/or Ni2O3 species on the surface of SnO2 nanoparticles, and their roles in the photo-absorb ability, photo-induced charge transfer and photocatalytic hydrogen evolution performances were also investigated under visible light irradiation. Pt/Ni2O3–SnO2 catalyst was not active for hydrogen evolution reaction, while the photocatalytic hydrogen evolution rates of Pt/Ni(OH)2–SnO2 and Pt/Ni(OH)2–Ni2O3–SnO2 were 0.9 and 10.8 μmol g−1 h−1, respectively. It indicated that the photocatalytic activity of Pt/Ni(OH)2–Ni2O3–SnO2 catalyst had been improved evidently in the presence of Ni2O3. The UV–vis DRS results showed that Ni(OH)2 enhanced light absorption of catalyst significantly in visible light region. The i–t curves confirmed that the co-existence of Ni(OH)2 and Ni2O3 improved significantly the photocurrent of Pt/Ni(OH)2–Ni2O3–SnO2 photo-electrode. In addition, the long term experiments revealed that Pt/Ni(OH)2–Ni2O3–SnO2 catalyst was quite stable under given conditions. A proposed reaction mechanism for hydrogen evolution was also present.

The behavior and effect of CuO in Ag/SnO2 materials

In this paper, the behavior of CuO in CuO-doped SnO2 nanoparticles was investigated; the effect of the addition of CuO on physical properties and arc erosion behavior of Ag/SnO2 materials were examined. The CuO-doped SnO2 nanoparticles were structurally characterized by X-ray diffraction (XRD) and High-resolution Transmission Electron Microscope (HR-TEM). The surface morphology of arc eroded Ag/SnO2 materials was characterized by Scanning Electron Microscope (SEM). The results indicated that the crystallized monoclinic CuO in CuO-doped SnO2 nanoparticles has formed and distributed on the surface of SnO2 nanoparticles. It was found that Ag/SnO2 materials adding CuO exhibited denser microstructure and better hardness as well as better arc erosion resistance compared with Ag/SnO2 materials. The arc erosion results and theoretical analysis indicated that the addition of CuO in Ag/SnO2 materials can obviously inhibited the spattering loss of molten droplets.

Influence of Particle Size and Water Coverage on the Thermodynamic Properties of Water Confined on the Surface of SnO2 Cassiterite Nanoparticles

Inelastic neutron scattering (INS) data for SnO2 nanoparticles of three different sizes and varying hydration levels are presented. Data were recorded on five nanoparticle samples that had the following compositions: 2 nm SnO2·0.82H2O, 6 nm SnO2·0.055H2O, 6 nm SnO2·0.095H2O, 20 nm SnO2·0.072H2O, and 20 nm SnO2·0.092H2O. The isochoric heat capacity and vibrational entropy values at 298 K for the water confined on the surface of these nanoparticles were calculated from the vibrational density of states that were extracted from the INS data. This study has shown that the hydration level of the SnO2 nanoparticles influences the thermodynamic properties of the water layers and, most importantly, that there appears to be a critical size limit for SnO2 between 2 and 6 nm below which the particle size also affects these properties and above which it does not. These results have been compared with those for isostructural rutile-TiO2 nanoparticles [TiO2·0.22H2O and TiO2·0.37H2O], which indicated that water on the surface of TiO2 nanoparticles is more tightly bound and experiences a greater degree of restricted motion with respect to water on the surface of SnO2 nanoparticles. This is believed to be a consequence of the difference in chemical composition, and hence surface properties, of these metal oxide nanoparticles.

Study of Structural Surface Modified Tin Oxide Membrane Prepared by Sol-Gel Route Sintered at 400°C

This work describes the chemical modification by Tiron® molecules of the surface of SnO2 nanoparticles used to prepare nanoporous membranes. Samples prepared with Tiron® content between 1 and 20 wt% and fired at 400°C were characterised by X-Ray Powder Diffraction (XRPD), Extended X-ray Absorption Fine Structure (EXAFS), N2 adsorption isotherms analysis and permeation experiments. XRPD and EXAFS results show a continuous reduction of crystallite size by increasing the Tiron® contents until 7.5 wt%. The control exercised by Tiron® modifying agent in crystallite growth allows the fine tuning of the average pore size that can be screened from 0.4 to 4 nm as the amount of grafted molecules decreases from 10 to 0 wt%. In consequence, the membrane cut-off can be screened from 1500 to 3500 g · mol−1.