scholarly journals Hydrothermal Synthesis and Hydrogen Sensing Properties of NanostructuredSnO2with Different Morphologies

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Weigen Chen ◽  
Hongli Gan ◽  
Wei Zhang ◽  
Zeyu Mao
Keyword(s):  
Specific Surface ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
Hydrogen Sensor ◽  
Pine Needle ◽  
Sensing Properties ◽  
Sensor Applications ◽  
Surface Areas ◽  
Sensing Material ◽  
Bet Analysis

In this work, nanoscale SnO2with various geometrical morphologies, including pine needle-like, sphere-like, sheet-like, grape-like nanostructures, was prepared via a facile hydrothermal process. Microstructures and morphologies of all the as-synthesized products were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Meanwhile, the specific surface areas of the as-prepared SnO2nanostructures were determined by Brunauer-Emmett-Teller (BET) analysis. Gas sensors were fabricated and their gas sensing properties towards hydrogen were systematically investigated. The results indicate pine needle-like SnO2structure exhibits exclusive better gas sensing performances to hydrogen than the other morphologies, which can be attributed to its novel shape with a large specific surface area. Such an unexpected morphology is a promising candidate for the use of SnO2as a gas sensing material in future hydrogen sensor applications.

Synthesis and Gas Sensing Properties of Urchin-Like CuO Self-Assembled by Nanorods through a Poly(ethylene glycol)-Assisted Hydrothermal Process

2009 ◽  
Vol 79-82 ◽  
pp. 1059-1062 ◽  
Author(s):  
Jiang Ying Li ◽  
Bao Juan Xi ◽  
Jun Pan ◽  
Yi Tai Qian
Keyword(s):  
Ethylene Glycol ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
Poly Ethylene Glycol ◽  
High Concentration ◽  
Hydrothermal Route ◽  
Xrd Pattern ◽  
Sensing Properties ◽  
Poly Ethylene ◽  
Ethanol Sensing

Urchin-like CuO, consisting of closely packed nanorods with a diameter of 10nm, have been successfully synthesized by a poly(ethylene glycol) (PEG)-assisted hydrothermal route at low temperature of 100°C. The as-obtained Urchin-like CuO were thoroughly characterized by X-ray diffraction (XRD) study, Field emission scanning electron microscope (FESEM), High-resolution transmission electron microscopy (HRTEM) and Gas sensor measurements. From the XRD pattern, all the peaks detected can be assigned to CuO in a monoclinic structure with lattice parameters a=4.662, b=3.416 and c=5.118 (JCPDS card no. 65-2309). The FESEM and TEM showed that the diameter of the urchin-like CuO sphere is about 1µm. Further investigation of the formation mechanism reveals that the PEG-assisted hydrothermal process is vital to the formation of 3D structures. Besides the template function, PEG often plays as a reductant while reacting with Cu(+2). In our case, no impurity peaks of Cu2O were observed in the XRD pattern, implying that PEG did not reduce Cu(+2) to Cu(+1). We attribute this to the high concentration of PEG. The sensor based on the urchin-like CuO nanostructures exhibit excellent ethanol-sensing properties at reduced working temperature (200°C), which shows a sensitivity two times higher than that of CuO particles(about 100nm, made from calcinations of Cu(NO3)2 at 400°C). The enhancement in sensitivity of the as-prepared CuO may be contributed to the fancy 3D nanostructures.

scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

scholarly journals New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Vo Thanh Duoc ◽  
Dang Thi Thanh Le ◽  
Nguyen Duc Hoa ◽  
Nguyen Van Duy ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Room Temperature ◽  
Gas Sensing ◽  
Local Heating ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Maximal Response ◽  
Sensor Applications ◽  
Sensing Characteristics ◽  
Sensing Performance

Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

scholarly journals Facile Hydrothermal Synthesis and Basic Gas-Sensing Properties of Two Three-Dimensional Nanostructures of SnO2

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lingna Xu ◽  
Weigen Chen ◽  
Caisheng Wang ◽  
Tuoyu Gao ◽  
Qu Zhou
Keyword(s):  
Gas Sensing ◽  
Three Dimensional ◽  
Hierarchical Architecture ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Sensor Applications ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Thin Nanosheets

The hierarchical SnO2sphere-like architecture, consisting of numerous thin nanosheets, was successfully synthesized via a facile hydrothermal method. The structures and morphologies of this hierarchical architecture were characterized in detail by means of powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET). Further comparative experiments of gas-sensing performances of the as-prepared SnO2were investigated towards ethanol. It shows this three-dimensional, sheet-spheres, SnO2as a potential gas-sensing material for a broad range of future sensor applications, like sensitive response to other gases such as hydrogen, carbonic oxide, and methane.

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.

Hierarchical Fe2O3@WO3 nanostructures with ultrahigh specific surface areas: microwave-assisted synthesis and enhanced H2S-sensing performance

RSC Advances ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 328-337 ◽  
Author(s):  
Li Yin ◽  
Deliang Chen ◽  
Mengjie Feng ◽  
Lianfang Ge ◽  
Dewei Yang ◽  
...  
Keyword(s):  
Specific Surface ◽  
Gas Sensing ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Wo3 Nanostructures ◽  
Microwave Assisted Method ◽  
Method Show ◽  
Sensing Performance

Fe2O3@WO3 composites with ultrahigh specific surface areas, synthesized via a simple microwave-assisted method, show high H2S gas-sensing performance.

scholarly journals Synthesis of Hollow ZnSnO3 Nanospheres with High Ethanol Sensing Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Qiong Wang ◽  
Na Yao ◽  
Chen Liu ◽  
Dongmin An ◽  
Yan Li ◽  
...  
Keyword(s):  
Gas Sensing ◽  
High Sensitivity ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Surface Areas ◽  
Transmission Electron ◽  
Hollow Nanostructures ◽  
Response And Recovery ◽  
Ethanol Sensing

Hollow ZnSnO3 nanospheres were synthesized by a hydrothermal method using ZnO nanospheres as the hard template and raw material simultaneously. The combined characterizations of X-ray diffraction (XRD), scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM) confirmed the successful preparation of hollow ZnSnO3 nanospheres. The gas-sensing results indicated that the sensor made from hollow ZnSnO3 nanospheres exhibited high sensitivity, good selectivity, and stability to ethanol at a low operating temperature of 200°C. The sensitivity was about 32 and the response and recovery time were about 4 s and 30 s for 100 ppm ethanol, respectively. The enhancement in gas-sensing properties was attributed to the hollow nanostructures and high specific surface areas of ZnSnO3.

Synthesis and Characterization of Hybrid ZnO@Ag Core-Shell Nanospheres for Gas Sensor Applications

2012 ◽  
Vol 710 ◽  
pp. 768-773 ◽  
Author(s):  
V. Ponnuvelu Dinesh ◽  
P. Biji ◽  
M. Kumaravel ◽  
A.K. Tyagi ◽  
M. Kamaruddin
Keyword(s):  
Surface Area ◽  
Gas Sensing ◽  
High Surface ◽  
High Surface Area ◽  
Silver Nanoclusters ◽  
Core Shell ◽  
Sensor Applications ◽  
Shell Nanostructures ◽  
Sensing Material ◽  
Interfacial Compatibility

ZnO nanospheres were prepared by hydrothermal method using CTAB as protecting ligands. The purified ZnO nanospheres were functionalized using 3-aminopropyl-trimethoxysilane (APTMS) and made into core-shell nanostructures with in-situ reduction of Ag+ into silver nanoclusters. ZnO nanospheres act as the core while silver nanoclusters act as shell material resulting in the formation of ZnO@Ag core-shell nanostructures. The precursor ZnO nanospheres and ZnO@Ag core-shell nanostructures were well characterised structurally by UV-Visible, FT-IR, XRD, and TGA and morphologically by SEM and HR-TEM. The analysis confirms that Ag nanoclusters are attached to ZnO nanospheres with uniform distribution. The induced surface area of these hybrid core-shell structures with isolated nanoclusters on ZnO surface pointed towards the possibility of having better sensitivity as an excellent gas sensing material. The present investigation provided an easy synthetic platform for obtaining high surface area core-shell nanostructures which enhances interfacial compatibility between metal oxide core and metal shell by suitable functionalization for generating better gas sensing materials.

Synthesis of flower-like Al doped ZnO microstructures by hydrothermal process and analysis of their gas sensing properties

2014 ◽  
Vol 07 (04) ◽  
pp. 1450037 ◽  
Author(s):  
Zan Li ◽  
Wei Qin ◽  
Wenjie Zhao ◽  
Xiaohong Wu
Keyword(s):  
Gas Sensing ◽  
Hydrothermal Process ◽  
Hexagonal Wurtzite Structure ◽  
Underlying Mechanism ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Doped Zno ◽  
Hydrothermal Approach

Al -doped ZnO (AZO) powders with flower-like microstructures were successfully synthesized through a simple and efficient hydrothermal approach, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy diffraction spectrum (EDS). All the samples presented high crystallinity with a hexagonal wurtzite structure. The heater gas sensors based on AZO were fabricated and investigation of gas sensing properties was conducted. The sensors showed high response values and reproducible response-recovery for 50–1800 ppm ethanol at 332°C, comparing with NH 3, SO 2, CO , and HCHO . The underlying mechanism was discussed.

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