Unravelling the Effect of Tb on the Surface Defects in ZnO Nanoparticles

2021 ◽  
pp. 90-95
Author(s):  
A. Sharma ◽  
V. N. Rai
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects

scholarly journals Precise Control of Surface Oxygen Vacancies in ZnO Nanoparticles for Extremely High Acetone Sensing Response

2021 ◽  
Author(s):  
Jihyun Lee ◽  
Youngmoon Choi ◽  
Byoung Joon Park ◽  
Jeong Woo Han ◽  
Hyun-Sook Lee ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Oxygen Vacancies ◽  
Surface Defects ◽  
High Sensitivity ◽  
Fast Response ◽  
Oxide Semiconductor ◽  
Surface Oxygen ◽  
Zno Nps ◽  
Precise Control ◽  
Optimal Surface

Abstract ZnO has been studied intensely for chemical sensors due to its high sensitivity and fast response. Here, we present a simple approach to precisely control oxygen vacancy contents to provide significantly enhanced acetone sensing performance of commercial ZnO nanopowders. A combination of H2O2 treatment and thermal annealing produces optimal surface defects with oxygen vacancies on the ZnO nanoparticles (NPs). The highest response of ~27,562 was achieved for 10 ppm acetone in 0.125 M H2O2 treated/annealed ZnO NPs at the optimal working temperature of 400 ℃, which is significantly higher than that of reported so far in various acetone sensors based on metal-oxide-semiconductor (MOS). Furthermore, first-principles calculations indicate that pre-adsorbed O formed on the surface of H2O2-treated ZnO NPs can provide a favorable adsorption energy, especially for acetone detection, due to strong bidentate bonding between carbonyl C atom of acetone molecules and pre-adsorbed O on the ZnO surface. Our study demonstrates that controlling surface oxygen vacancies by H2O2 treatment and re-annealing at optimal temperature is an effective method to improve the sensing properties of commercial MOS materials.

scholarly journals Formation of surface defects by thermal shock method for the improved photocatalytic activity of ZnO nanoparticles

2020 ◽  
Vol 8 (1) ◽  
pp. 193-202 ◽  
Author(s):  
Tien Khoa Le ◽  
The Luan Nguyen ◽  
Chau Ngoc Hoang ◽  
Dieu Khanh An Nguyen ◽  
Torben Lund ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Thermal Shock ◽  
Zno Nanoparticles ◽  
Surface Defects

Effect of surface defects on the visible emission from ZnO nanoparticles

2007 ◽  
Vol 22 (9) ◽  
pp. 2404-2409 ◽  
Author(s):  
Harish Kumar Yadav ◽  
K. Sreenivas ◽  
Vinay Gupta ◽  
S.P. Singh ◽  
R.S. Katiyar
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Hexagonal Wurtzite Structure ◽  
Liquid Nitrogen Temperature ◽  
Intermediate Compound ◽  
Band Edge Emission ◽  
Zinc Hydroxide ◽  
Hydroxyl Groups ◽  
Green Luminescence ◽  
Zno Crystal

The luminescent property of ZnO nanoparticles prepared using the wet chemical method has been investigated. The ZnO nanoparticles in the range 5–10 nm exhibit hexagonal Wurtzite structure, and the photoluminescence (PL) spectrum at room temperature shows a broad visible luminescence band and insignificant near-bandgap emission. The broad green luminescence is dominant at both room and boiled off liquid-nitrogen temperature, while the ultraviolet band edge emission is strongly quenched. The prepared ZnO nanoparticles have residual intermediate compound on the surface in the form of an acetate group, which acts as defect centers for the emission of green luminescence. A trace amount of zinc hydroxide is observed in one of the samples and is found to further enhance the intensity of the green luminescence. Raman scattering studies on nanoparticles indicate that the acetate/hydroxyl groups are loosely bound on the surface and are not present in the interior of the ZnO crystal structure

The role of l-cysteine and introduced surface defects in reactive oxygen species generation by ZnO nanoparticles

2018 ◽  
Vol 47 (25) ◽  
pp. 8320-8329 ◽  
Author(s):  
Dominika Wawrzyńczyk ◽  
Bartłomiej Cichy ◽  
Wiesław Stęk ◽  
Marcin Nyk
Keyword(s):  
Reactive Oxygen Species ◽  
Surface Functionalization ◽  
Zno Nanoparticles ◽  
Surface Defects ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Oxygen Species

The synthesis and surface functionalization of ZnO nanoparticles were performed, with attention being paid to the possible bio-related applications in light-triggered reactive oxygen species generation.

Effect of Surface Defects on Green Luminescence from ZnO Nanoparticles

2011 ◽  
Author(s):  
Surender Kumar ◽  
P. D. Sahare ◽  
S. K. Tripathi ◽  
Keya Dharamvir ◽  
Ranjan Kumar ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Green Luminescence ◽  
Effect Of Surface

scholarly journals Structural, Optical, and Photocatalytic Activities of Ag-Doped and Mn-Doped ZnO Nanoparticles

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Mengstu Etay Ashebir ◽  
Gebrekidan Mebrahtu Tesfamariam ◽  
Gebretinsae Yeabyo Nigussie ◽  
Tesfakiros Woldu Gebreab
Keyword(s):  
Zno Nanoparticles ◽  
Surface Defects ◽  
Visible Region ◽  
Methyl Violet ◽  
Secondary Phases ◽  
Photocatalytic Decolorization ◽  
Vis Spectroscopy ◽  
Photocatalytic Activities ◽  
Doped Zno ◽  
Mn Doped

We report the photocatalytic activities of ZnO, Ag-doped ZnO, and Mn-doped ZnO nanoparticles (NPs). Ag-doped and Mn-doped ZnO samples were synthesized using a coprecipitation method and calcined at 600°C. XRD, SEM, EDX, and UV-vis spectroscopy techniques were employed for characterization of the synthesized samples. The photocatalytic activities of the samples were evaluated by measuring the photocatalytic decolorization of methyl violet with sunlight being the source of energy. XRD patterns of the samples confirmed the wurtzite structure without change which was indicative of the absence of Mn- and Ag-related secondary phases for the doped ZnO. The UV-vis spectra indicated the band gap energy of ZnO, Ag-doped ZnO, and Mn-doped ZnO to be 2.98, 2.80, and 2.64 eV, respectively. Photocatalytic decolorization of methyl violet for the synthesized samples was found to be favorable at a pH of 9.0, catalyst dose of 1 g/L, and initial dye concentration of 4.5 × 10−4 g/L. Mn-doped ZnO and Ag-doped ZnO photocatalytic decolorization efficiency was significantly higher than undoped ZnO. Incorporation of Mn and Ag enhanced the visible-light photocatalytic activity of ZnO; this could be due to the ability of these metals to increase the surface defects of ZnO which in turn shift their optical absorption towards the visible region.

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