Effect of Al-doping on the structure and optical properties of electrospun zinc oxide nanofiber films

Yun, Sining; Lim, Sangwoo

doi:10.1016/j.jcis.2011.05.022

Cited by 37 publications

(7 citation statements)

References 58 publications

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“…The intensity of (020) diffraction peak decreased and full width at half maxima increased with increase in TiO 2 content, indicating the poor crystallinity and reduction of crystallite size. These structural changes are due to differences in the ionic radii between the impurity ion and host consistent with Vegard's law [26] which states that if the ionic radius of the host atom is larger than the ionic radius of dopant atom it leads to a decrease in crystallinity. In the present study, the dopant atom Ti 4+ ion (0.68 Å) has smaller substituting radius for the larger ionic radius of host atom Cd 2 + ion (1.07 Å) resulted decrease i n crystallinity.…”

Section: Resultssupporting

confidence: 56%

CdO-TiO2 nanocomposite thin films for resistive hydrogen sensing

2015

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A resistive gas sensor for hydrogen (H 2 ) was developed using CdO-TiO 2 nanocomposite films deposited onto a glass substrate in a thickness of typically 300-450 nm by co-sputtering. X-ray diffraction patterns confirmed the formation of a perovskite CdTiO 3 phase. Field emission-scanning electron micrographs showed spherically shaped grains which decreased in size on increasing the TiO 2 concentration, most probably due to difference in the size of the ions of Cd and Ti. The nanostructured films with lower concentration of TiO 2 exhibited good response to H 2 at an operating temperature of 275°C and an operating voltage of 250 mV. The sensors give a 3 % relative resistance change on exposure to 500 ppm of H 2 , have a 45 s response time and a 90 s recovery time. The H 2 sensor described here does not require expensive additives and thus may find both civilian and industrial applications.

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Section: Resultssupporting

confidence: 56%

CdO-TiO2 nanocomposite thin films for resistive hydrogen sensing

2015

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“…The TT‐Nb 2 O 5 /M‐NbO 2 CE exhibits the lowest R s value among all the CEs, implying good adhesion to the fluorine‐doped tin oxide (FTO) substrates, which can be identified by its compact surface structure. To improve the adhesion of the electrode films to the FTO substrates, several effective techniques have been illustrated [8a,34]. The R ct value is a major parameter for evaluating the catalytic activity for I 3 − reduction [30d,35].…”

Section: Resultsmentioning

confidence: 99%

Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid‐Junction Photovoltaic Devices

Yun

Shi

et al. 2019

Solar RRL

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Two types of nanosized niobium oxides and their composites, pseudohexagonal Nb2O5 (TT‐Nb2O5), monoclinic NbO2 (M‐NbO2), and the coexistence of TT‐Nb2O5 and M‐NbO2 (TT‐Nb2O5/M‐NbO2), are successfully synthesized through the urea‐metal chloride route, and they exhibit excellent catalytic activity and photovoltaic performance in dye‐sensitized solar cells (DSSCs). First‐principles density function theory (DFT) calculations show that their catalytic activity is significantly influenced by their intrinsic electronic structures and properties. The lone‐pair 4d1 electrons of Nb4+ in M‐NbO2 enhance the Nb–I interaction and promote electron transfer from the M‐NbO2 counter electrode (CE) to I, thus resulting in superior catalytic properties in M‐NbO2‐based DSSCs. In addition, the adsorption energy of I on the M‐NbO2 surface is in the optimal energy range of 0.3—1.2 eV, and the Fermi level of M‐NbO2 is 0.6 eV, which is higher than the I3− reduction reaction potential, and I3− can be spontaneously reduced to 3I−. Herein, a general strategy for understanding the electronic structures and catalytic activities of transition metal compounds as CE catalysts for DSSCs is provided.

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“…TiO 2 and ZnO, which are benchmark UV photocatalysts have very low activity in visible light due to their wide band gaps (above 3 eV) [73,74]. In order to apply sunlight for photocatalytic degradation of contaminants, the semiconductors need to be modified by incorporation of transition metals [75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94], semiconductor plasmon coupling [72,[95][96][97][98][99][100][101], incorporating nonmetals including co-doping of nonmetals [102][103][104][105][106] or by nanostructure engineering (creating oxygen vacancies and oxygen sub-stoichiometry) [107,108]. These processes create quasi stable energy states within the band gap facilitating electron hole pair formation at photon energies less than the band gap [33,34,[109][110][111][112].…”

Section: Making Zno Visible Light Activementioning

confidence: 99%

Nanostructured Zinc Oxide for Water Treatment

Baruah¹,

Pal²,

Dutta

2012

NANOASIA

143

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Environmental pollution and industrialization on a global scale have drawn attention to the vital need for developing new hygienically friendly purification technologies. Existing wastewater treatment technologies demand high capital investment and operation & maintenance cost, and large area. Cost-effective treatment of pollutants requires the transformation of hazardous substances into benign forms and the subsequent development of effective risk management strategies from harmful effects of pollutants that are highly toxic, persistent, and difficult to treat. Application of nanotechnology that results in improved water treatment options might include removal of the finest contaminants from water (< 300 nm) and "smart materials" or "reactive surface coatings" with engineered specificity to a certain pollutant that destroy, transform or immobilize toxic compounds. Nanomaterials have been gaining increasing interest in the area of environmental remediation mainly due to their enhanced surface and also other specific changes in their physical, chemical and biological properties that develop due to size effects. Heterogeneous photocatalytic systems via metal oxide semiconductors like TiO 2 and ZnO, are capable of operating effectively and efficiently for waste water treatment which has been discussed along with other nanotechnology routes that can be useful for water treatments. Multifunctional photocatalytic membranes using ZnO nanostructures are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. A short discussion on the study of charge transfer mechanisms during photocatalytic reactions has also been included.

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Effect of Al-doping on the structure and optical properties of electrospun zinc oxide nanofiber films

Cited by 37 publications

References 58 publications

CdO-TiO2 nanocomposite thin films for resistive hydrogen sensing

CdO-TiO2 nanocomposite thin films for resistive hydrogen sensing

Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid‐Junction Photovoltaic Devices

Nanostructured Zinc Oxide for Water Treatment

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