Journal ArticleDOI
Gas sensing properties of ZnO nanostructures (flowers/rods) synthesized by hydrothermal method
Sonalika Agarwal,Prabhakar Rai,Prabhakar Rai,Eric Navarrete Gatell,Eduard Llobet,Frank Güell,Manoj Kumar,Kamlendra Awasthi +7 more
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TLDR
In this article, the authors reported the hydrothermal synthesis of flower-shaped ZnO nanostructures and investigated their morphology-dependent gas sensing properties using X-ray diffraction and scanning electron microscopy.Abstract:
Here, we report the hydrothermal synthesis of flower-shaped ZnO nanostructures and investigated their morphology-dependent gas sensing properties. Scanning electron microscope (SEM) study confirmed the formation of two kinds of floral structures. At short reaction time, flower-like structures (2–3 μm in size) composed of nanoparticles are formed, whereas floral assemblies (˜ 5 μm) of nanorods are formed at long reaction time. X-ray diffraction (XRD) confirmed the formation of the hexagonal wurtzite structure of ZnO. The average crystallite size of prepared nanoflowers and nanorods were found to be 21 nm and 43 nm, respectively. These results are supported by transmission electron microscopy (TEM). The band gap of ZnO nanostructures was calculated from the UV–vis absorption spectrum and found to be 3.0 eV and 3.19 eV for ZnO nanoflowers and nanorods, respectively. Broad absorption peak in the visible region of photoluminescence (PL) spectra confirmed the presence of oxygen vacancies in both specimens. Furthermore, morphology dependent gas sensing property was investigated for ethanol, benzene, carbon monoxide, and nitrogen dioxide at different operating temperatures and concentrations. Although both morphologies have shown good sensitivity and selectivity towards NO2 at ppb, the response of nanoflower was higher than that of nanorods, which was attributed to its relatively higher surface area and amount of surface defects.read more
Citations
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Photoluminescence of ZnO Nanowires: A Review.
TL;DR: The photoluminescence (PL) properties of single and collective ZnO nanowires and nanorods are reviewed and a summary of the different native point defects or trap centers in ZNO as a cause for the different deep-level emission bands is presented.
Journal ArticleDOI
ZnO as a Functional Material, a Review
TL;DR: In this article, the authors provide a wide-ranging cross-section of the current state of ZnO structures and technologies, with the main development directions underlined, serving as an introduction, a reference, and an inspiration for future research.
Journal ArticleDOI
Review of ZnO-based nanomaterials in gas sensors
TL;DR: ZnO-based gas sensors have been widely used due to fast response, low detection limit, high selectivity, reliable performance and low manufacturing cost as discussed by the authors, however, their sensitivity and selectivity are low.
Journal ArticleDOI
Nanostructured Metal Oxide-Based Acetone Gas Sensors: A Review
TL;DR: Different aspects of metal oxide-based acetone gas sensors in pristine, composite, doped, and noble metal functionalized forms are discussed and gas sensing mechanisms are discussed.
Journal ArticleDOI
Rapid detection of low concentration CO using Pt-loaded ZnO nanosheets.
TL;DR: According to the measurement results, the loading of Pt remarkably upgraded the sensing capability toward CO, and Pt/ZnO is an efficient sensor material for rapidly detecting low-concentration CO.
References
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Journal ArticleDOI
Conduction Model of Metal Oxide Gas Sensors
Nicolae Barsan,Udo Weimar +1 more
TL;DR: In this article, the authors provide a frame model that deals with all contributions involved in conduction within a real world sensor, and then summarize the contributions together with their interactions in a general applicable model for real world gas sensors.
Journal ArticleDOI
Detection of hazardous volatile organic compounds (VOCs) by metal oxide nanostructures-based gas sensors: A review
TL;DR: In this paper, the authors extensively review recent developments in this field, focusing the attention on the detection of some common VOCs, including acetone (C3H6O), acetylene (C2H2), benzene (C6H6), cyclohexene (Cyclohexenene) and 2-propanol (C7H8O), by means of conductometric solid state sensors based on nanostructured semiconducting metal oxides.
Journal ArticleDOI
XPS and optical studies of different morphologies of ZnO nanostructures prepared by microwave methods
TL;DR: In this paper, a comparative study between three different morphologies of ZnO nanostructures, namely nanoparticles (NPs), nanoflowers (NFs) and nanorods (NRs), has been presented.
Journal ArticleDOI
Zinc Oxide Nanostructures for NO2 Gas–Sensor Applications: A Review
TL;DR: Various factors such as NO2 concentrations, annealing temperature, ZnO morphologies and particle sizes, relative humidity, operating temperatures which are affecting the NO2 gas sensing properties are discussed in this review.
Journal ArticleDOI
Synthesis, characterization and optical properties of zinc oxide nanoparticles
TL;DR: In this article, a simple precipitation method with zinc sulfate and sodium hydroxide as starting materials was used to synthesize ZnO nanoparticles, which were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and proton-induced Xray emission (PIXE) analysis.
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