Ordered Titanium Dioxide Nanotubular Arrays as Photoanodes for Hydrogen Generation

Misra, M.; Raja, Krishnan S.

doi:10.1002/9780470823996.ch10

Cited by 8 publications

(9 citation statements)

References 54 publications

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“…4b and c can be attributed to the formation of hydrogen bonding between the O0C-N bond of PAAm with the silanols and/or aluminols of HNTs. Interestingly, a new peak at 288.4 eV were found, which is assigned to carbon of carbonate-type species at a confined environment of PAAm chains for the dried NC gels because of the interactions between PAAm and the nanotubes [27]. Consequently, the XPS results together with the FTIR results confirm the formation of hydrogen bonding in the NC gel systems.…”

Section: Interactions Between Paam and Hntssupporting

confidence: 51%

Novel polymer nanocomposite hydrogel with natural clay nanotubes

2012

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presence of nanoclay in aqueous system. Here, novel natural tube-like nanoparticles, halloysite nanotubes (HNTs), are firstly used as multifunctional cross-linkers for polyacrylamide (PAAm) to form a new type of organic/inorganic hybrid hydrogels. Significant improvements in mechanical properties of the PAAm-HNTs NC gels are found by the addition of HNTs as shown by the static mechanical testing and dynamic viscoelasticity measurement. HNTs are uniformly dispersed in the NC gels from the morphological result. HNTs can be intercalated by PAAm chains as observed by the X-ray diffraction result. Hydrogen bonding interactions between HNTs and PAAm are confirmed by the infrared spectroscopy and X-ray photoelectron spectroscopy. The maximum equilibrium degree of swelling (EDS) for the NC gel is 4000% and the EDS decreases with the concentration of clay nanotubes. The present work provides a novel routine for preparing NC gels using "green" onedimensional nanoparticle. The prepared NC gels have promising application in biomedical areas due to the superior mechanical properties of the gels and good biocompatibility of HNTs.Keywords Halloysite nanotubes . Hydrogel . Mechanical properties . Nanocomposite mer and inorganic nanoparticle was first proposed and fabricated by Haraguchi, a Japanese scientist, in 2002 [1]. The NC gels can be synthesized through in situ free-radical polymerization of water-soluble monomers such as acrylamide and 2-methoxyethylacrylate in the presence of nanoclay in aqueous system, in which the nanoclays act as the multifunctional cross-linking points for the polymer chains [2][3][4]. Compared with traditional organic cross-linked hydrogel, the NC gels have a unique structure and properties, for example, super optical transparency, ultrahigh tensile extensibility, high swollen ratio and stimuli sensitivities [2]. Therefore, NC gels have been found to be applicable as super-absorbent materials, biomedical materials, smart materials, and so on. A wide range of clay minerals with layered crystal structures, good water swellability, and strong interactions with the water soluble monomers are used as the inorganic component for the NC gels. Typical examples include the smectite-group clays (hectorite, saponite, montmorillonite and so on) and mica-group clays (synthetic fluorine mica). Among these, the artificially synthesized layered silicate "Laponite," with the molecular formula of [Mg 5.34 Li 0.66 Si 8 O 20 (OH) 4 ]Na 0.66 , is mostly used for the preparation of NC gels. Laponite has sufficiently small platelet size (30 nm (diameter)×1 nm (thickness)) and high swelling ability in water (about 35×) for forming clear and colorless colloid dispersion. A series of NC gels have been prepared by combining Laponite with different monomers [1,[4][5][6]. The ability of forming inorganic/organic hybrid network for NC gels depends on the interactions between the nanoclay and the monomer/polymers, such as, hydrogen bonding and/or ionic interaction. On the other hand, the NC gels cannot be obtained by the polymer...

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Section: Interactions Between Paam and Hntssupporting

confidence: 51%

Novel polymer nanocomposite hydrogel with natural clay nanotubes

2012

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“…The synthesis of vertically orientated self-ordered metal oxide nanotube arrays on metal substrates using electrochemical anodization technique have been reviewed [ 6 , 7 , 8 ], as well as their application in solar energy conversion systems [ 9 , 10 , 11 , 12 , 13 ]. Although several highly ordered nanotubular-type oxide structures of various valve metals and their alloys have been achieved through electrochemical anodization, this review will focus on some of the more recent metal oxide nanotube architectures that have demonstrated solar-based applications, more specifically titania nanotube arrays.…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently, steady-state growth of the nanotubular oxide layer is observed when the current density achieves a constant value over time (region iii). It should be noted that the anodic current density during anodization is comprised of two components: the first is current due to the dissolution process at the oxide/electrolyte interface, and the second is current due to the oxidation of titanium at the metal/oxide interface [ 9 ]. Moreover, pH of the electrolyte plays a large role in the pore nucleation and growth of the nanotubes as the dissolution rate of the oxide increases with a decrease in pH [ 58 ].…”

Section: Introductionmentioning

confidence: 99%

Self-Ordered Titanium Dioxide Nanotube Arrays: Anodic Synthesis and Their Photo/Electro-Catalytic Applications

et al. 2013

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Metal oxide nanotubes have become a widely investigated material, more specifically, self-organized titania nanotube arrays synthesized by electrochemical anodization. As a highly investigated material with a wide gamut of applications, the majority of published literature focuses on the solar-based applications of this material. The scope of this review summarizes some of the recent advances made using metal oxide nanotube arrays formed via anodization in solar-based applications. A general methodology for theoretical modeling of titania surfaces in solar applications is also presented.

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“…26,27 For further details on the formation mechanism and applications of titania nanotube arrays, readers are directed to the recent review works of Schmuki 28 and Misra. 29 Despite the widespread applications of TiO 2 −NTA, the majority of studies on TiO 2 −NTA remain in the realm of solarbased applications because of enhanced charge transport properties from the 1D architecture. As a result, several studies have been conducted on different methods to improve the photoactivity of TiO 2 −NTA through band gap engineering (doping), 30−32 functionalizing/sensitizing with cocatalysts/ heterostructure, 8,33−35 plasma surface treatments, 36 or used as a precursor to synthesize other photoactive materials such as bismuth titanate.…”

Section: Introductionmentioning

confidence: 99%

“…Concave as well as nonplanar or curved substrates such as wires , or mesh − have also been used for nanotube growth. We have also recently demonstrated site-specific and patterned growth of TiO 2 –NTA on thin sputtered films of Ti on Si wafer. , For further details on the formation mechanism and applications of titania nanotube arrays, readers are directed to the recent review works of Schmuki and Misra …”

Section: Introductionmentioning

confidence: 99%

Light-Assisted Anodized TiO₂ Nanotube Arrays

Smith

Sarma

Mohanty

et al. 2012

ACS Appl. Mater. Interfaces

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Self-assembled arrays of titania nanotubes are synthesized via electrochemical anodization of Ti foils under the presence of UV-vis irradiation. Compared to control samples (anodized without light), the light-assisted anodized samples exhibit larger diameters as well as thicker nanotube walls, whereas the length of the nanotubes remains the same under otherwise similar synthesis conditions. Enhanced photoelectrochemical performance with light-assisted anodized samples under simulated AM 1.5 irradiation is observed by an increase in photocurrent density of 45-73% at 1.23 V (RHE). The enhanced photoelectrochemical performance is correlated to improved charge separation analyzed by Mott-Schottky. A mechanism on the photoeffect during anodization is presented. The morphology and improved properties obtained from the synthesis methodology may also find application in other fields such as sensing and catalysis.

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Ordered Titanium Dioxide Nanotubular Arrays as Photoanodes for Hydrogen Generation

Cited by 8 publications

References 54 publications

Novel polymer nanocomposite hydrogel with natural clay nanotubes

Novel polymer nanocomposite hydrogel with natural clay nanotubes

Self-Ordered Titanium Dioxide Nanotube Arrays: Anodic Synthesis and Their Photo/Electro-Catalytic Applications

Light-Assisted Anodized TiO₂ Nanotube Arrays

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Ordered Titanium Dioxide Nanotubular Arrays as Photoanodes for Hydrogen Generation

Cited by 8 publications

References 54 publications

Novel polymer nanocomposite hydrogel with natural clay nanotubes

Novel polymer nanocomposite hydrogel with natural clay nanotubes

Self-Ordered Titanium Dioxide Nanotube Arrays: Anodic Synthesis and Their Photo/Electro-Catalytic Applications

Light-Assisted Anodized TiO2 Nanotube Arrays

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Light-Assisted Anodized TiO₂ Nanotube Arrays