Nanostructured mesoporous NiO as an efficient photocatalyst for degradation of methylene blue: Structure, properties and performance

Maniammal, K.; Madhu, Gaurav; Biju, Vasudevanpillai

doi:10.1016/j.nanoso.2018.07.007

Cited by 34 publications

(20 citation statements)

References 74 publications

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“…Therefore, in this work, the Raman-active modes are in agreement with the previous reports regarding the NiO phase and indicate the presence of Ni 2+ vacancies introduced by controlling the synthesis conditions and calcination temperature, resulting in a non-stoichiometric NiO. 36 , 41 …”

Section: Resultssupporting

confidence: 91%

Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

et al. 2020

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Black NiO powders were prepared by a hydrothermal method. Moreover, the visible light-driven Ag 3 PO 4 /NiO photocatalyst composites were successfully synthesized by in situ precipitation method. These samples were structurally characterized by X-ray diffraction and Rietveld refinement. The strong interaction between the phases and the defects in the samples was affected by the formation of the composites, as identified by Fourier transform infrared spectroscopy and Raman spectroscopy. UV–vis diffuse reflectance spectroscopy exhibited enhanced light absorption for all Ag 3 PO 4 /NiO composites, suggesting the effective interaction between the phases. Moreover, field-emission scanning electron microscopy images revealed the presence of NiO microflowers composed of nanoflakes in contact with Ag 3 PO 4 microparticles. The composite with 5% NiO presented enhanced photocatalytic efficiency in comparison with pure Ag 3 PO 4 , degrading 96% of rhodamine B (RhB) dye in just 15 min under visible light; however, the recycling experiments confirmed that the composite with 75% NiO showed superior stability. The recombination of the electron–hole pairs was considered for the measurement of the photoluminescence of the samples. These measurements were performed to evaluate the possible causes for the difference in the photocatalytic responses of the composites. From these experimental results, possible photocatalytic mechanisms for RhB degradation over Ag 3 PO 4 /NiO composites under visible-light irradiation were proposed.

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Section: Resultssupporting

confidence: 91%

Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

et al. 2020

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“…In the composites also, the NiO crystallites show lattice expansion in comparison with bulk NiO and with increase in the average crystallite size, lattice expansion decreases. This is in agreement with previous reports on the lattice expansion in nanocrystalline NiO where the lattice expansion decreases with increase in the crystallite size [9,[36][37][38]. Lattice expansion in NiO has been attributed to the formation of point defects, grain-surface-relaxation effect, uncompensated Coulomb interactions, etc.…”

Section: X-ray Diffraction Analysissupporting

confidence: 92%

“…Lattice expansion in NiO has been attributed to the formation of point defects, grain-surface-relaxation effect, uncompensated Coulomb interactions, etc. [9,36]. TEM image of sample E shown in Fig.…”

Section: X-ray Diffraction Analysismentioning

confidence: 99%

“…Thus, in the present case though the electronic band gap is not much varied in the composites in comparison with pure ZnO, the charge separation efficiency is increased due to the formation of p-n heterojunctions. Over and above the decrease in the free charge carrier recombination efficiency, the d-d transitions in NiO due to the absorption of photons with energies lower than the band gap also contribute to the photocatalytic action of the composite due to the formation of holes in the valence band of NiO [9]. The decomposition of the methylene blue dye is due to the formation of both super oxide anion radical O 2 ·− and hydroxide radicals OH · at the surface of the catalysts.…”

Section: Photocatalytic Performancementioning

confidence: 99%

“…This technique is complementary to the conventional approaches of waste water treatment such as filtration and sedimentation [1]. Wide band-gap semiconductors such as TiO 2 , ZnO, SnO 2 , WO 3 , Fe 2 O 3 , CdS and NiO are some of the most actively investigated systems as photocatalysts for water purification [2][3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Enhanced photocatalytic activity of ZnO–NiO nanocomposites synthesized through a facile sonochemical route

et al. 2019

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Formation of heterostructures with p-type oxides such as NiO and CuO is one of the effective methods for improving the photocatalytic performance of ZnO. Such systems are often synthesized through template-based growth techniques that involve many steps. We have prepared ZnO-NiO composites through a facile, template-free, low-temperature sonochemical route. High-resolution transmission electron microscopy analysis indicates the formation of ZnO-NiO heterostructures. Photocatalytic activity of ZnO-NiO nanocomposites in the decomposition of methylene blue dye under solar irradiation is found to be much larger than that of both pure ZnO (1.26 × 10 −2 min −1 ) and NiO (0.31 × 10 −2 min −1 ) establishing synergistic effects. The rate constant increases with increase in the percentage of NiO in the composite and is 6.00 × 10 −2 min −1 for sample with the highest percentage of NiO. Rate constants for the second and third runs are estimated to be 4.4 × 10 −2 and 4.2 × 10 −2 min −1 which are promising. The main mechanism of enhancement of photocatalytic activity of the composites is identified as the more effective separation of the photogenerated free charge carries due to the internal electric field at the ZnO-NiO interface. Sharp decrease in the relative intensity of the band-band emission of ZnO at ~ 380 nm in the case of composite samples and analysis of the relative position of the conduction band and valence band edges of ZnO and NiO support the proposed mechanism.

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Synthesis of Core/Shell (ZnO/Ag) Nanoparticles Using Calotropis gigantea and Their Applications in Photocatalytic and Antibacterial Studies

Kumar¹,

Betageri²,

Nagaraju

et al. 2020

J Inorg Organomet Polym

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Nanostructured mesoporous NiO as an efficient photocatalyst for degradation of methylene blue: Structure, properties and performance

Cited by 34 publications

References 74 publications

Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

Enhanced photocatalytic activity of ZnO–NiO nanocomposites synthesized through a facile sonochemical route

Synthesis of Core/Shell (ZnO/Ag) Nanoparticles Using Calotropis gigantea and Their Applications in Photocatalytic and Antibacterial Studies

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Nanostructured mesoporous NiO as an efficient photocatalyst for degradation of methylene blue: Structure, properties and performance

Cited by 34 publications

References 74 publications

Ag3PO4/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

Ag3PO4/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

Enhanced photocatalytic activity of ZnO–NiO nanocomposites synthesized through a facile sonochemical route

Synthesis of Core/Shell (ZnO/Ag) Nanoparticles Using Calotropis gigantea and Their Applications in Photocatalytic and Antibacterial Studies

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Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light

Ag₃PO₄/NiO Composites with Enhanced Photocatalytic Activity under Visible Light