NiO-based nanostructures with efficient optical and electrochemical properties for high-performance nanofluids

Gangwar, Jitendra; Dey, Kajal Kumar; Tripathi, S. K.; Wan, Meher; Yadav, Raja Ram; Singh, Rajiv Kumar; Samta,; Srivastava, Avanish Kumar

doi:10.1088/0957-4484/24/41/415705

Cited by 58 publications

(40 citation statements)

References 77 publications

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“…The peak at 2384 cm À1 substantiates to the absorption of atmospheric CO 2 [47,48]. Rutile provides evidence of some extra peaks at around 1028 and 1165 cm À1 that can be substantiated to carbonate ions and their presence can be due to the dissolution of CO 2 from air [49,50]. The two bands at 2514 and 2922 cm À1 represent the combination bands [51].…”

Section: Ftir Spectroscopymentioning

confidence: 77%

Interactions of titania based nanoparticles with silica and green-tea: Photo-degradation and -luminescence

Verma

Awasthi

Srivastava

et al. 2016

Journal of Colloid and Interface Science

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An effective way to modify the photocatalytic activity of both anatase and rutile TiO2 nanoparticles by coating the surface with either an inorganic (SiO2/silica) or organic (green-tea) layer using a chemical approach is demonstrated. Tetraethyl orthosilicate (TEOS) was used to cover the surface of TiO2 with silica which facilitates the inhibition of photocatalytic activity, ensuring its application in sunscreens by blocking the reactive oxygen species (ROS). Green-tea extract, rich in epigallocatechin gallate (EGCG), was used to coat/stabilize nano-sized TiO2. The morphology of these coatings was revealed by transmission electron microscopy (TEM) and by energy dispersive spectroscopy (EDS) mapping. These studies showed good coverage for both types of coating, but with somewhat better uniformity of the coating layer on rutile TiO2 compared to anatase due to its more uniform particle geometry. The effectiveness of each coating was evaluated by photodegradation of an organic dye (methyl orange). These studies showed rutile_polyphenol exhibits the highest photocatalytic activity among rutile forms which validates its feasibility to be used in photodegradation.

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Section: Ftir Spectroscopymentioning

confidence: 77%

Interactions of titania based nanoparticles with silica and green-tea: Photo-degradation and -luminescence

Verma

Awasthi

Srivastava

et al. 2016

Journal of Colloid and Interface Science

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“…The dehydration process is accompanied by oxolation mechanism and subsequently forms O-Ni-O bridges. 47 Thus, improper calcination leads to unsaturated OH groups, anionic and cationic vacancies on the surface of nNiO. Also, nNiO has proven its ability to adsorb ionic impurities from aqueous solutions on to the active sites on its surface.…”

Section: 42-45mentioning

confidence: 99%

Low-voltage electro-optical memory device based on NiO nanorods dispersed in a ferroelectric liquid crystal

et al. 2016

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We present a low voltage driven electro-optical memory device fabricated by dispersing nano-sized nickel oxide (nNiO) composed of short length nanorods into a ferroelectric liquid crystal (FLC) host material. The nNiO/FLC composite showed a tremendous decrease in saturation voltage compared to the pristine FLC material along with non-volatile memory behavior which is confirmed through dielectric spectroscopy, polarized optical microscopy and electro-optical response methods. This drop off in saturation voltage is due to the fast alignment of dipolar nNiO and mesogens in the nNiO/FLC composite along the direction of the applied electric field and reduced screening effect. The non-volatile memory behavior of the composite is attributed to the reduction in the depolarization field by adsorption of impurity ions onto the surface of nNiO, which is verified through dielectric spectroscopy and electrical conductivity measurements. These studies pave the way for fabricating non-volatile, low power electro-optical memory devices for advanced information storage applications.

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“…[1][2][3][4][5][6][7][8][9]19 Such increment in the heat transport characteristics of base fluids suggests the crucial benefits which give credence to liquid coolants for moving heat away from electronic, optical, machinery, or nuclear reactor systems. [5][6][7]9 Various nanoparticles (NPs) of metals and metal oxides have been added to EG for enhancing the thermal conductivity (TC) of base fluid and are potentially used in heat transfer system. 2,[5][6][7][8][9]19,21,[23][24][25] The nanofluids based on EG reveal a higher TC having nonlinear relationship with temperature.…”

Section: O 3 Nanoparticlesmentioning

confidence: 99%

“…[5][6][7]9 Various nanoparticles (NPs) of metals and metal oxides have been added to EG for enhancing the thermal conductivity (TC) of base fluid and are potentially used in heat transfer system. 2,[5][6][7][8][9]19,21,[23][24][25] The nanofluids based on EG reveal a higher TC having nonlinear relationship with temperature. 23,29 A very recent report to examine the effects of nanoparticle size and temperature has been published focusing on the TC enhancement of water-based Al 2 O 3 nanfluids.…”

Section: O 3 Nanoparticlesmentioning

confidence: 99%

Strong enhancement in thermal conductivity of ethylene glycol-based nanofluids by amorphous and crystalline Al2O3 nanoparticles

Gangwar

Srivastava

Tripathi

et al. 2014

Applied Physics Letters

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In the present work, the temperature and concentration dependence of thermal conductivity (TC) enhancement in ethylene glycol (EG)-based amorphous and crystalline Al2O3 nanofluids have been investigated at temperatures ranging from 0 to 100 °C. In our prior study, nanometer-sized particles of amorphous-, γ-, and α-Al2O3 were prepared via a simple sol-gel process with annealing at different temperatures and characterized by various techniques. Building upon the earlier study, we probe here the crystallinity, microstructure, and morphology of the obtained α-Al2O3 nanoparticles (NPs) by using X-ray powder diffraction with Rietveld full-profile refinement, scanning electron microscopy, and high-resolution transmission electron microscopy, respectively. In this study, we achieved a 74% enhancement in TC at higher temperature (100 °C) of base fluid EG by incorporating 1.0 vol. % of amorphous-Al2O3, whereas 52% and 37% enhancement is accomplished by adding γ- and α-Al2O3 NPs, respectively. The amorphous phase of NPs appears to have good TC enhancement in nanofluids as compared to crystalline Al2O3. In a nutshell, these results are demonstrating the potential consequences of Al2O3 NPs for applications of next-generation efficient energy transfer in nanofluids.

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NiO-based nanostructures with efficient optical and electrochemical properties for high-performance nanofluids

Cited by 58 publications

References 77 publications

Interactions of titania based nanoparticles with silica and green-tea: Photo-degradation and -luminescence

Interactions of titania based nanoparticles with silica and green-tea: Photo-degradation and -luminescence

Low-voltage electro-optical memory device based on NiO nanorods dispersed in a ferroelectric liquid crystal

Strong enhancement in thermal conductivity of ethylene glycol-based nanofluids by amorphous and crystalline Al2O3 nanoparticles

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