Formation of urchin-like ZnO nanostructures by sol-gel electrophoretic deposition for photocatalytic application

Taheri, Mahtab; Abdizadeh, Hossein; Golobostanfard, Mohammad Reza

doi:10.1016/j.jallcom.2017.07.173

Cited by 42 publications

(15 citation statements)

References 50 publications

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“…Zinc oxide (ZnO) is known as an important semiconductor for its favorable properties as transparency [1], high electron mobility [2], wide band gap [3], tough room temperature [4] and luminescence [5]. In the last few years, there has been a growing interest of the researchers, focusing on the synthesis of nanocrystalline ZnO, hence, many methods, including sol-gel [6][7][8][9]. Thereby, particle size and crystal morphology play important roles in all applications, like nanodevices for opto-electronic [10], gas sensing [11], photocatalytic activity [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of polyethylene glycol and propyltrimethoxysilane on structural and optical properties of zinc oxide nanoparticles synthesized by sol–gel process

et al. 2018

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Zinc oxide nanoparticles (ZnO NPs) are prepared by sol-gel process, using both polyethylene glycol (PEG-400) as surfactant and propyltrimethoxysilane (PTMS) as capping agent. Surface modification is performed in situ procedure. The physical parameters such as strain and stress values are calculated via the Williamson-Hall plot (W&H) assuming a uniform deformation model (UDM) and uniform stress deformation model, and by the size and strain plot method (SSP). The results show that the crystallite size estimated from Scherrer's formula, (W&H), (UDM), (SSP) and the particle size estimated from DSL are inter-correlated, which confirm the small size and the isotropic nature of our ZnO NPs. The FTIR spectroscopy illustrates that PEG-400 and PTMS could be adsorbed at the ZnO NPs surface. The distinct emission peak in the blue band is located at 490 nm and E 2 (high) mode is situated at 436 cm -1 . Both results confirm the oxygen deficiency in the ZnO NPs.

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Section: Introductionmentioning

confidence: 99%

Effect of polyethylene glycol and propyltrimethoxysilane on structural and optical properties of zinc oxide nanoparticles synthesized by sol–gel process

et al. 2018

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“…Wahab et al [45] fabricated ZnO nano-flowers with blunt tapering via pH-controlled reactions in a solution of zinc acetate dihydrate and sodium hydroxide at 90 • C. Using a similar approach, Gokarna et al [46] synthesised ZnO urchin-like structures with columnar nanoneedles. Hieu et al [47] sputtered zinc onto a polystyrene-sphere array and subsequent oxidation at 500 • C led to columnar ZnO urchins; while the method used by Taheri et al [48] also involved depositing zinc acetate dihydrate precursor followed by calcination at 500 • C. The solution synthesis method we report here is relatively simpler (at RT and applicable to different surfaces as we show below) compared to these previous studies, producing spiky tapered morphology of the urchin needles with a very high density previously unreported. The presence of high-density spiky ZnO urchins endows the surface with multi-functionalities as discussed below.…”

Section: Resultsmentioning

confidence: 99%

“…Several fabrication methods of ZnO nanostructured surfaces have been reported [21][22][23][24][25][26][27][28], such as hydrothermal synthesis, laser ablation, sputtering, thermal decomposition, evaporation induced self-assembly [29,30], and the sol-gel technique. Various ZnO nanostructures that have been reported include one-dimensional (1-D) morphologies such as nanowires [31][32][33], nanofibers [29,30], nanorods [34][35][36][37], micro-dendrites [38,39], and nanotubular structures [40][41][42][43][44], as well as 3-D architectures such as flowers/urchins [45][46][47][48][49][50], tetrapods/jack-like [51,52], and hedgehogs [53]. The 3-D nanostructures with enhanced surface area may be used as substitutes for 1-D nanostructure arrays with enhanced functionalities, but their fabrication requires either sophisticated instrumentation or elevated temperatures (and thus high energy input).…”

Section: Introductionmentioning

confidence: 99%

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Tripathy

Wąsik

Sreedharan

et al. 2018

Colloids and Interfaces

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Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report the simple fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, µm-long, tapered nanoneedles radiating from the urchin center. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of "infant" urchins at the early growth stage and subsequent progressive increases in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH) 2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth times were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins-with spiky nanoneedles and at high surface density-on Si substrates was demonstrated. First, bacteria colonization was found to be suppressed on the surface after 24 h incubation in gram-negative Escherichia coli (E. coli) culture, in contrast to control substrates (bare Si and Si sputtered with a 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ∼ 0 • , could be rendered superhydrophobic with a simple silanization step, characterized by an apparent water contact angle θ of 159 • ± 1.4 • and contact angle hysteresis ∆θ < 7 • . The dynamic superhydrophobicity of the surface was demonstrated by the bouncing-off of a falling 10 µL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200-800 nm. The ZnO urchins with a unique morphology fabricated via a simple route at room temperature, and readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.

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“…Taheri et al 46 also involved depositing zinc acetate dihydrate precursor followed by calcination at obtained with a high surface coverage (Figure 3a, c), with urchins found on orthorhombic -Zn(OH)2 crystal facets (Figure 3b). There was no significant difference in the urchin morphology (urchin size φ, needle length L, diameter D, and tip angle ) compared to the seeded substrate.…”

Section: Resultsmentioning

confidence: 99%

“…Several fabrication methods of ZnO nanostructured surfaces have been reported [21][22][23][24][25][26][27][28] , such as hydrothermal synthesis, laser ablation, sputtering, thermal decomposition, evaporation induced self-assembly 29,30 , and the sol-gel technique. Various ZnO nanostructures that have been reported include one-dimensional (1-D) morphologies such as nanowires [31][32][33] , nanorods [34][35][36][37] , and nanotubular structures [38][39][40][41][42] , as well as 3-D architectures such as flowers/urchins [43][44][45][46][47][48] , tetrapods/jack-like 49,50 , and hedgehogs 51 . The 3-D nanostructures with enhanced surface area may be used as substitutes for 1-D nanostructure arrays with enhanced functionalities, but their fabrication requires either sophisticated instrumentation or elevated temperatures (thus high energy input).…”

Section: Introductionmentioning

confidence: 99%

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Tripathy¹,

Wąsik²,

Sreedharan³

et al. 2018

Preprint

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Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report facile fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, μm-long, tapered nanoneedles radiating from the urchin centre. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of “infant” urchins at the early growth stage and subsequent progressive increase in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH)2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth time were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins—with spiky nanoneedles and at high surface density—on Si substrates was demonstrated. First, bacteria colonisation was found to be suppressed on the surface after 24 h incubation in Gram-negative E. coli culture, in contrast to control substrates (bare Si and Si sputtered with 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ~0°, could be rendered superhydrophobic with a simple silanization step, characterised by a water static contact angle θ of 159° ± 1.4° and contact angle hysteresis ∆θ < 7°. The dynamic superhydrophobicity of the surface was demonstrated by bouncing-off of a falling 10 μL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200–800 nm. The ZnO urchins with unique morphology via a facile fabrication route at room temperature, readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.

show abstract

Formation of urchin-like ZnO nanostructures by sol-gel electrophoretic deposition for photocatalytic application

Cited by 42 publications

References 50 publications

Effect of polyethylene glycol and propyltrimethoxysilane on structural and optical properties of zinc oxide nanoparticles synthesized by sol–gel process

Effect of polyethylene glycol and propyltrimethoxysilane on structural and optical properties of zinc oxide nanoparticles synthesized by sol–gel process

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

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