K4Nb6O17-derived photocatalysts for hydrogen evolution from water: Nanoscrolls versus nanosheets

Sarahan, Mike; Carroll, Elizabeth C.; Allen, Mark; Larsen, Delmar S.; Browning, Nigel D.; Osterloh, Frank E.

doi:10.1016/j.jssc.2008.06.021

Cited by 99 publications

(84 citation statements)

References 22 publications

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“…12,[16][17][18][22][23][24][25]59,73 To our knowledge, this is the first report of SEI images of hexaniobate nanoscrolls. Comparing the SEI image of the LbL film of PANI-NbONsc in Fig.…”

Section: 222459mentioning

confidence: 78%

“…12,[16][17][18][19][20][21][22] In addition, many authors have reported that the exfoliation of hexaniobate (NbO) with tetra(n-butyl)ammonium hydroxide (TBAOH) promotes the curling of the exfoliated nanosheets, resulting in 1D metal oxide nanoparticles known as hexaniobate nanoscrolls (NbONsc). 16,17,[22][23][24] The processes of hexaniobate exfoliation and formation of NbONsc are simplified and shown in Scheme 1. Although the mechanisms of the nanosheets curling and the nanoscrolls stabilization are not well elucidated, NbONsc have been used to produce hybrid materials for photo-production of H 2 and O 2 , 17,23,24 and for encapsulation of magnetic nanoparticles.…”

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confidence: 99%

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Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

et al. 2012

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The combination of semiconducting oxides and polyaniline in the nanoscale range may result in hybrid materials having enhanced properties, such as electrochromism and charge capacity. This paper reports the spectroscopic, morphological and electrochromic characterization of hybrid films made up of hexaniobate one-dimensional (1D) nanoscrolls and polyaniline prepared by the layer-by-layer assembly technique (LbL). Secondary electron imaging and backscattered electron imaging techniques performed using a scanning electron microscope showed that polyaniline is adsorbed on the hexaniobate nanoscrolls, which confirms the combination of the components in the nanoscale domain. UV-VIS-NIR electronic spectra of the LbL hybrid films showed the absorption tail in the NIR region, assigned to delocalized polarons of the polyaniline. Resonance Raman spectra in the 1000-1700 cm À1 range indicated that hybrid films present a higher relative intensity of polaron bands at 1337 and 1508 cm À1 than pristine polyaniline in the emeraldine salt form. These results suggest that hexaniobate nanoscrolls induce a secondary doping of polyaniline. The cyclic voltammetry (CV) data for the hybrid film showed a specific capacity of 870 C cm À3 . According to CV results, the synergistic effect on charge storage properties of the hybrid material is attributed to the enhanced electroactivity of the hexaniobate component in the LbL film. Spectroelectrochemical experiments showed that the electrochromic efficiencies at 420 nm are ca. À41 and 24 cm 2 C À1 as the potential changes from 0.8 to À0.9 V and from À0.9 to À1.8 V, respectively, whereas at 800 nm the efficiencies are ca. À55 and 8 cm 2 C À1 for the same potential ranges. The electrochromic efficiencies and multi-colour character of the LbL film of hexaniobate nanoscrolls and polyaniline indicate that this novel hybrid material is an interesting modified electrode for electrochromic devices.

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“…12,[16][17][18][22][23][24][25]59,73 To our knowledge, this is the first report of SEI images of hexaniobate nanoscrolls. Comparing the SEI image of the LbL film of PANI-NbONsc in Fig.…”

Section: 222459mentioning

confidence: 78%

mentioning

confidence: 99%

Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

et al. 2012

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“…The transfer of charge carriers to the surface takes place in a similar manner to 1D structures and helps to enhance performance. 201,[212][213][214][215][216] Pure TiO 2 NS surfaces are catalytically inactive as a result of the presence of a large over-potential and fast backward reaction (generation of H 2 O), whereas surface-fluorinated Pt-TiO 2 NSs have significant catalytic activity. 217 However, in sharp contrast, ultrathin TiO 2 NSs showed a high catalytic activity as a result of a shorter migration time, which suppressed recombination.…”

Section: Two-dimensional Nanostructuresmentioning

confidence: 99%

Review of one-dimensional and two-dimensional nanostructured materials for hydrogen generation

Babu

Vempati

Uyar

et al. 2015

Phys. Chem. Chem. Phys.

161

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Hydrogen is an attractive alternative to fossil fuels in terms of environmental and other advantages. Of the various production methods for H 2 , photocatalysis requires further development so that it can be applied economically on an industrial scale. One-and two-dimensional nanostructures in both pristine and modified forms have shown great potential as catalysts in the generation of H 2 . We review here recent developments in these nanostructure catalysts and their efficiency in the generation of H 2 under UV/visible/simulated solar light. Despite much research effort, many photocatalysts do not yet meet the practical requirements for the generation of H 2 , such as visible light activity. H 2 production is dependent on a variety of parameters and factors. To meet future energy demands, several challenges in H 2 production still need to be solved. We address here the factors that influence the efficiency of H 2 production and suggest alternatives. The nanostructures are classified based on their morphology and their efficiency is considered with respect to the influencing parameters. We suggest effective ways of engineering catalyst combinations to overcome the current performance barriers.

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“…Potassium hexaniobate is a layered oxide semiconductor consisting of [Nb 6 O 17 ] 4À sheets, which are formed by sharing edges or by corners of distorted NbO 6 octahedral units [36] (Figure 8 A). To maintain the charge balance of the system, K + ions are located in the interlayer region.…”

Section: Discussionmentioning

confidence: 99%

Selective Synthesis of Silver Nanoparticles onto Potassium Hexaniobate: Structural Organisation with Bactericidal Properties

et al. 2013

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Silver-based nanocomposites are known to act as biocides against a series of microorganisms and are largely studied as an alternative to substitute conventional antibiotics that show decreasing efficacy. In this work, an eco-friendly method to synthesize silver nanoparticles assembled on the surface of hexaniobate crystals is reported. By means of ion exchange, K(+) ions of layered potassium hexaniobate were partially substituted by Ag(+) ions and the resulting material was exposed to UV light. The irradiation allowed the reduction of silver ions with consequent formation of silver nanoparticles located only on the hexaniobate surface, whereas Ag(+) ions located in the interlayer space remained in the ionic form. Increasing UV-light exposure times allowed controlling of the silver nanoparticle size. The antibacterial effects of the pristine potassium hexaniobate and of silver-containing hexaniobate samples were tested against Escherichia coli (E. coli). The antibacterial efficacy was determined to be related to the presence of silver in hexaniobate. An increasing activity against E. coli was observed with the decrease in silver nanoparticles size, suggesting that silver nanoparticles of distinct sizes interact differently with bacterial cell walls.

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K4Nb6O17-derived photocatalysts for hydrogen evolution from water: Nanoscrolls versus nanosheets

Cited by 99 publications

References 22 publications

Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

Review of one-dimensional and two-dimensional nanostructured materials for hydrogen generation

Selective Synthesis of Silver Nanoparticles onto Potassium Hexaniobate: Structural Organisation with Bactericidal Properties

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