scholarly journals C2H5OH and NO2 sensing properties of ZnO nanostructures: correlation between crystal size, defect level and sensing performance

RSC Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 5629-5639 ◽  
Author(s):  
Chu Thi Quy ◽  
Nguyen Xuan Thai ◽  
Nguyen Duc Hoa ◽  
Dang Thi Thanh Le ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Crystal Size ◽  
Gas Sensing ◽  
Zno Nanostructures ◽  
Defect Level ◽  
Sensing Applications ◽  
Sensing Performance

ZnO nanostructures were synthesized for ethanol and nitrogen dioxide gas-sensing applications. Results pointed out that the defect levels dominating the gas-sensing performance but not the morphology, specific surface area or crystal size.

scholarly journals Surface Structure Engineering of Nanosheet-Assembled NiFe2O4 Fluffy Flowers for Gas Sensing

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 297
Author(s):  
Xiaofeng Wang ◽  
Xu Li ◽  
Guozheng Zhang ◽  
Zihao Wang ◽  
Xue-Zhi Song ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Adsorption Desorption ◽  
Sensing Performance

In this work, we present a strategy to improve the gas-sensing performance of NiFe2O4 via a controllable annealing Ni/Fe precursor to fluffy NiFe2O4 nanosheet flowers. X-ray diffraction (XRD), a scanning electron microscope (SEM), nitrogen adsorption–desorption measurements and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure, morphology, specific surface area and surface structure. The gas-sensing performance was tested and the results demonstrate that the response was strongly influenced by the specific surface area and surface structure. The resultant NiFe2O4 nanosheet flowers with a heating rate of 8 °C min−1, which have a fluffier morphology and more oxygen vacancies in the surface, exhibited enhanced response and shortened response time toward ethanol. The easy approach facilitates the mass production of gas sensors based on bimetallic ferrites with high sensing performance via controlling the morphology and surface structure.

P–p heterojunction CuO/CuCo2O4 nanotubes synthesized via electrospinning technology for detecting n-propanol gas at room temperature

2017 ◽  
Vol 4 (7) ◽  
pp. 1219-1230 ◽  
Author(s):  
Khaled Tawfik Alali ◽  
Zetong Lu ◽  
Hongsen Zhang ◽  
Jingyuan Liu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Room Temperature ◽  
Gas Sensing ◽  
Tubular Structure ◽  
Large Specific Surface Area ◽  
Sensing Performance

Composite CuO/CuCo2O4 nanotubes were synthesized by electrospinning technology. The large specific surface area, complex tubular structure, and p–p heterojunction are the potential reasons for the excellent room temperature gas sensing performance toward n-propanol vapor.

Effect of Crystals Size, Surface Area and Pore Size of Hydroxyapatite Microspheres on the Loading Ability of Bovine Serum Albumin

2011 ◽  
Vol 197-198 ◽  
pp. 17-20
Author(s):  
Jun Ming Li ◽  
Ai Juan Wang ◽  
Yu Peng Lv ◽  
Bai Ling Jiang
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Bovine Serum ◽  
Crystal Size ◽  
Adsorption Ability ◽  
Before And After

Effect of crystals size, surface area, pore size and porosity of hydroxyapatite microspheres on the loading ability of bovine serum albumin was studied in this paper. The surface morphology, specific surface area and porosity of hydroxyapatite microspheres were characterized by scanning electron microscope, specific surface area and pore size analyzer, respectively. The concentration of BSA in aqueous solutions both before and after adsorption was determined by ultraviolet-visible spectrophotometer. The results indicated that the adsorption behavior of bovine serum albumin appeared to obey the Langmuir-type isotherm model. Fast adsorption appeared at the beginning, and then decreased gradually. Hydroxyapatite microspheres calcined at 600°C had the maximum capacity, and those calcined at 800°C showed lower adsorption ability. The loading ability of hydroxyapatite microspheres depended on its crystal size, specific surface area, pore size and porosity, etc.

scholarly journals Preparation and Application of 2D MXene-Based Gas Sensors: A Review

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 225
Author(s):  
Qingting Li ◽  
Yanqiong Li ◽  
Wen Zeng
Keyword(s):  
Composite Materials ◽  
Specific Surface ◽  
Surface Area ◽  
Gas Sensor ◽  
Specific Surface Area ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Interlayer Spacing ◽  
Preparation Methods

Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.

scholarly journals W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 836
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Alessia Amodio ◽  
Mauro Mazzocchi ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Gas Sensing ◽  
Molar Fraction ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

scholarly journals Effect of Ethanol on the Morphology and Textual Properties of ZSM-5 Zeolite

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 198
Author(s):  
Xiuru Liu ◽  
Yiqing Sun
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Crystal Size ◽  
Ethanol Concentration ◽  
Textural Properties ◽  
Oh Groups ◽  
And Diffusion

The morphology of ZSM-5 zeolite impacts the adsorption, separation and diffusion of molecules. The morphology and textural properties of ZSM-5 zeolites were adjusted by regulating the content of ethanol in the synthesis gel. When the ratio of ethanol/SiO2 was lower than 2, the obtained crystals were isolated particles. With higher ethanol concentration, the chainlike zeolite was generated due to the condensation of terminal Si-OH groups. The crystals stacked more and more compactly with the increase in ethanol concentration, resulting in decreased specific surface area, total volume and mesoporous volume. The crystal size increased gradually with the increase in the ethanol concentration. Moreover, some other small molecular alcohols could also induce the formation of chainlike morphology of ZSM-5.

Template-free preparation of mesoporous single crystal In2O3 achieving superior ethanol gas sensing performance

RSC Advances ◽  
2016 ◽  
Vol 6 (18) ◽  
pp. 14615-14619 ◽  
Author(s):  
Jijiang Liu ◽  
Gang Chen ◽  
Yaoguang Yu ◽  
Yalin Wu ◽  
Mingjun Zhou ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Specific Surface ◽  
Single Crystal ◽  
Surface Area ◽  
Gas Sensing ◽  
Vacancy Concentration ◽  
High Specific Surface Area ◽  
Oxygen Vacancy Concentration ◽  
Template Free ◽  
Sensing Performance

Mesoporous single crystal In2O3 with high specific surface area and oxygen vacancy concentration are prepared for enhanced ethanol gas sensing performance.

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