scholarly journals Improved Methane Sensing Properties of Co-Doped SnO2Electrospun Nanofibers

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Weigen Chen ◽  
Qu Zhou ◽  
Lingna Xu ◽  
Fu Wan ◽  
Shudi Peng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
High Performance ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Two Samples ◽  
Electrospinning Method ◽  
Co Doped

Co-doped SnO2nanofibers were successfully synthesized via electrospinning method, and Co-doped SnO2nanospheres were also prepared with traditional hydrothermal synthesis route for comparison. The synthesized SnO2nanostructures were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectra. Planar-type chemical gas sensors were fabricated and their sensing properties to methane were investigated in detail. Gas sensors based on these two samples demonstrate the highest CH4sensing response at an operating temperature of 300°C. Compared with traditional SnO2nanospheres, the nanofiber sensor shows obviously enhanced gas response, higher saturated detection concentration, and quicker response-recovery time to methane. Moreover, good stability, prominent reproducibility, and excellent selectivity are also observed based on the nanofibers. These results demonstrate the potential application of Co-doped SnO2nanofibers for fabricating high performance methane sensors.

Methanol Sensing Properties of Electrospun SnO2 -ZnO Nanofibers

2011 ◽  
Vol 356-360 ◽  
pp. 565-568
Author(s):  
Shao Hong Wei ◽  
Mei Hua Zhou ◽  
Wei Ping Du
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Promoting Effect ◽  
Heterojunction Structure ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Zno Nanofibers ◽  
Scanning Electron

Pure ZnO and SnO2-ZnO nanofibers were synthesized by electrospinning method and characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structure and methanol sensing properties of these fibers were investigated. The results indicate that the 20 wt% SnO2-ZnO sensor exhibits considerable sensitivity, rapid response, and good selectivity against methanol at 200 °C due to the special 1D fibers properties and the promoting effect of SnO2/ZnO heterojunction structure. The methanol sensing mechanism of SnO2-ZnO nanofibers were also discussed.

scholarly journals Ni2P/rGO/NF Nanosheets As a Bifunctional High-Performance Electrocatalyst for Water Splitting

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 744 ◽  
Author(s):  
Jinyu Huang ◽  
Feifei Li ◽  
Baozhong Liu ◽  
Peng Zhang
Keyword(s):  
Electron Microscopy ◽  
Water Splitting ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Efficiency ◽  
Splitting Method ◽  
Bifunctional Catalyst ◽  
Strong Activity ◽  
X Ray ◽  
Transmission Electron

The hydrogen generated via the water splitting method is restricted by the high level of theoretical potential exhibited by the anode. The work focuses on synthesizing a bifunctional catalyst with a high efficiency, that is, a nickel phosphide doped with the reduced graphene oxide nanosheets supported on the Ni foam (Ni2P/rGO/NF), via the hydrothermal approach together with the calcination approach specific to the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The Raman, X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscope (TEM), Scanning Electron Microscopy (SEM), High-Resolution Transmission Electron Microscopy (HRTEM), as well as elemental mapping, are adopted to study the composition and morphology possessed by Ni2P/rGO/NF. The electrochemical testing is performed by constructing a parallel two-electrode electrolyzer (Ni2P/rGO/NF||Ni2P/rGO/NF). Ni2P/rGO/NF||Ni2P/rGO/NF needs a voltage of only 1.676 V for driving 10 mA/cm2, which is extremely close to Pt/C/NF||IrO2/NF (1.502 V). It is possible to maintain the current density for no less than 30 hours. It can be demonstrated that Ni2P/rGO/NF||Ni2P/rGO/NF has commercial feasibility, relying on the strong activity and high stability.

Synthesis of La2NiO4+δ Nanofibers by Electrospinning Method and their Application

2018 ◽  
Vol 281 ◽  
pp. 859-864
Author(s):  
Yan Xing ◽  
Meng Fei Zhang ◽  
Tian Jun Li ◽  
Wei Pan
Keyword(s):  
Electron Microscopy ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Mixed Conductivity ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Electrospinning Method

La2NiO4+σ nanofibers exhibiting typical Ruddlesden–Popper structure (K2NiO4) were fabricated by a facile electrospinning method. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to analyze the structure, morphology and crystal process of the La2NiO4+σ nanofibers. For electrical properties measurement, uniaxially aligned nanofibers were directly collected and assembled into electrode. In our research, La2NiO4+σ phase forms above 873K with no impurity phase emerges during the thermal treatments. The nanofibers are smooth and uniform throughout the entire length and the grain is growing as calcination temperature increases. Furthmore, the La2NiO4+σ nanofibers own high mixed conductivity at 773K, laying good foundation for intermediate temperature solid oxide fuel cells application.

scholarly journals Synthesis of NiW Supported on an Al-Modified Cubic Ia3d Mesoporous KIT-5 Catalyst and Its Hydrodenitrogenation Performance of Quinoline

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1183
Author(s):  
Xing Liu ◽  
Shaoqing Guo ◽  
Xin Li ◽  
Lijing Yuan ◽  
Hongyu Dong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fourier Transform ◽  
Three Dimensional ◽  
Fourier Transform Infrared ◽  
Photoelectron Spectra ◽  
Sulfide Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Large Pore Size

Pure KIT-5 and a series of Al-KT-X materials modified by different amounts of aluminum were synthesized by a direct hydrothermal method and acted as supports for the catalysts of a quinoline hydrodenitrification reaction with the NiW active phases supported. The results of X-ray diffraction (XRD), N2 isotherm absorption-desorption, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) for the supports indicated that Al species were embedded into the framework of the KIT-5 materials with a large pore size, pore volume, and specific surface area. The Pyridine-Fourier transform infrared spectroscopy (Py-IR) result of the catalysts demonstrated that the addition of aluminum atoms enhanced the acidity of the catalysts. The results of the high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectra (XPS) characterizations for the sulfide catalysts indicated that the embedded Al species could facilitate the dispersion of active metals and the formation of the active phases. Among all the catalysts, NiW/Al-KT-40 showed the maximal hydrodenitrogenation conversion (HDNC) due to its open three-dimensional pore structure, appropriate acidity, and good dispersion of active metals.

scholarly journals Low Working Temperature of ZnO-MoS2 Nanocomposites for Delaying Aging with Good Acetylene Gas-Sensing Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1902
Author(s):  
Sijie Wang ◽  
Weigen Chen ◽  
Jian Li ◽  
Zihao Song ◽  
He Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Morphological Characteristics ◽  
Molar Ratio ◽  
X Ray ◽  
Sensing Properties ◽  
Working Temperature ◽  
Current Concerns

The long-term stability and the extension of the use time of gas sensors are one of the current concerns. Lowering the working temperature is one of the most effective methods to delay aging. In this paper, pure MoS2 and ZnO-MoS2 nanocomposites were successfully prepared by the hydrothermal method, and the morphological characteristics were featured by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Pure MoS2 and ZnO-MoS2 nanocomposites, as a comparison, were used to study the aging characteristic. The sensing properties of the fabricated gas sensors with an optimal molar ratio ZnO-MoS2 (Zn:Mo = 1:2) were recorded, and the results exhibit a high gas-sensing response and good repeatability to the acetylene detection. The working temperature was significantly lower than for pure MoS2. After aging for 40 days, all the gas-sensing response was relatively attenuated, and pure MoS2 exhibits a faster decay rate and lower gas-sensing response than nanocomposites. The better gas-sensing characteristic of nanocomposites after aging was possibly attributed to the active interaction between ZnO and MoS2.

ZnS NANOFLOWERS ON GRAPHENE FOR USE AS A HIGH-PERFORMANCE PHOTOCATALYST

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450097 ◽  
Author(s):  
ZENG BIN ◽  
LONG HUI
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Dye Degradation ◽  
Uv Light ◽  
Xps Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Potential Applications

The nanocomposites of graphene loaded– ZnS nanoflowers (GR– ZnS ) had been successfully prepared. Materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) spectra. A possible formation mechanism of this architecture was proposed. The experimental results revealed that these nanoflowers exhibited excellent UV-light photocatalytic activities for pollutant methyl orange (MO) dye degradation. These new nanostructures were expected to show considerable potential applications in the water treatment.

scholarly journals Facile and Rapid Synthesis of Ultrafine PtPd Bimetallic Nanoparticles and Their High Performance toward Methanol Electrooxidation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Tiantian Xia ◽  
Hanrui Shen ◽  
Gang Chang ◽  
Yuting Zhang ◽  
Honghui Shu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Performance ◽  
Direct Methanol Fuel Cells ◽  
Bimetallic Nanoparticles ◽  
Methanol Electrooxidation ◽  
X Ray ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Direct Methanol

Uniform and sub-10 nm size bimetallic PtPd nanoparticles (NPs) have been synthesized via a simple and facile method without using any surfactants at an ambient temperature. As a green and clean reductive agent, ascorbic acid (AA) was employed for the coreduction of K2PtCl4and K2PdCl4in aqueous solution. The morphology, composition, and structure of PtPd NPs had been characterized by transmission electron microscopy (TEM), field emission high resolution transmission electron microscopy (FE-HRTEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscope (XPS). Comparing with both the monometallic Pt and Pd, the as-prepared alloy nanoparticles show superior electrocatalytic activity and better tolerance against poisoning by intermediates generated during methanol electrooxidation, which makes them a promising electrocatalysts for direct methanol fuel cells (DMFCs). Meanwhile, the green and simple approach could be easily extended to the manufacture of bimetallic or trimetallic alloy nanomaterials.

Synthesis and Luminescence Properties of Yb3+/Ho3+ Co-Doped Lu2O3 Nanocrystalline Powders

2007 ◽  
Vol 280-283 ◽  
pp. 521-524
Author(s):  
Li Qiong An ◽  
Jian Zhang ◽  
Min Liu ◽  
Sheng Wu Wang
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Nanocrystalline Powders ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Co Doped

Yb3+ and Ho3+ co-doped Lu2O3 nanocrystalline powders were synthesized by a reversestrike co-precipitation method. The as-prepared powders were examined by the X-ray diffraction and transmission electron microscopy. The phase composition of the powders was cubic and the particle size was in the range of 30~50 nm. Emission and excitation spectra of the powders were measured by a spectrofluorometer and the possible upconversion luminescence mechanism was also discussed.

Effect of Calcinations on Morphology of Electrospun Copper and Copper Oxide Nanofibers

2011 ◽  
Vol 52-54 ◽  
pp. 1884-1889 ◽  
Author(s):  
Dariush Jafar Khadem ◽  
Zahira Yaakob ◽  
Samaneh Shahgaldi ◽  
Wan Ramli Wan Daud ◽  
Edy Herianto Majlan
Keyword(s):  
Electron Microscopy ◽  
Copper Oxide ◽  
Sol Gel ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Nanostructures ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Potential Applications

Metal and Metal oxide nanofibers have different potential to play an essential role in a series of application, among them copper and copper oxide nanostructures is a promising semiconductor material with potential applications in many field. In this paper, electrospinning method via sol-gel was used to fabricate copper and copper oxide nanofibers. Synthesize of copper and copper oxide nanofibers and also effect of calcinations temperature on morphology investigated by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).

Synthesis of Al Doped ZnO with a Novel Rice Microstructure by Hydrothermal Process and Analysis of their Gas Sensing Properties

2014 ◽  
Vol 809-810 ◽  
pp. 724-730
Author(s):  
Zan Li ◽  
Wei Qin ◽  
Xiao Hong Wu
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
Hexagonal Wurtzite Structure ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Doped Zno ◽  
Hydrothermal Approach

Al-doped ZnO (AZO) powers with a novel rice-like morphology have been successfully synthesized through a simple and efficient hydrothermal approach, the products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy-dispersive X-ray analyzer and transmission electron microscopy (TEM). It showed that all the samples presented an hexagonal wurtzite structure of high crystallinity, and the microstructure was composed of numerous dumbbells. Furthermore, the heater gas sensors were fabricated and an investigation of gas sensing properties has been conducted. The sensors showed good selectivity to ethanol comparing with NH3, SO2, CO and HCHO and possible mechanism was discussed. The Sensors based AZO powers exhibited high response values, reproducible response-recovery to ethanol 50-1800 ppm at 332°C.

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