Surface Phases and Photocatalytic Activity Correlation of Bi2O3/Bi2O4-x Nanocomposite

Hameed, Abdul; Montini, Tiziano; Gombac, Valentina; Fornasiero, Paolo

doi:10.1021/ja803603y

Cited by 328 publications

(185 citation statements)

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“…Current doubling was observed with the addition of organic hole scavengers such as alcohols, formate, and aldehydes in other semiconductor electrodes like ZnO, CdS, and [34][35][36] However, under similar experimental conditions this phase transformation was inhibited in bismuth oxide based nanocomposites. 37,38 To the best of the authors' knowledge, formation of Bi 2 O 4-x in the Bi 2 O 3 materials under solar water splitting conditions has not been reported earlier.…”

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confidence: 94%

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting

Chitrada

Gakhar

Chidambaram

et al. 2016

J. Electrochem. Soc.

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Ordered nanoporous bismuth oxide layer consisting of metastable β-Bi 2 O 3 phase that showed n-type semiconductivity was synthesized by a simple electrochemical anodization of bismuth substrate. When the anodic nanoporous β-Bi 2 O 3 samples were tested as photoanodes for solar water splitting application in 0.5 M Na 2 SO 4 (pH:5.8), and 1 M KOH (pH:13.7), the photocurrent decayed continuously with time from an initial value of 0.95 mA/cm 2 under 1-sun illumination at a bias potential of 1.5 V RHE . Accumulation of photo generated holes at the photoanode/ electrolyte was attributed to the photocurrent decay. Addition of methanol as sacrificial hole scavenger was not found to be effective for the bismuth oxide photoanodes. When hydrogen peroxide was added to the 0.5 M Na 2 SO 4 electrolyte, the photocurrent density increased to ∼4 mA/cm 2 and was stable for more than 1 h of illumination of AM1.5 global light at 1.5 V RHE . Addition of hydrogen peroxide to the 1 M KOH solution showed a gradual increase in the photocurrent density for the first 300 seconds of light illumination to a maximum value of ∼10 mA/cm 2 at 0.65 V RHE and then it decreased continuously. The high photocurrent density of nanoporous β-Bi Bismuth based mixed oxides such as BiVO 4 , BiFeO 3 , BiWO 6 , Bi 3 NbO 7 , and Bi 2 MoO 6 are being actively investigated as promising high efficiency photocatalysts for solar water splitting applications. 1-11These bismuth based oxides show predominantly n-type semiconductivity and therefore function as photoanodes in the photoelectrochemical water splitting process. A significant amount of literature is available on the photoelectrochemical behavior of bismuth based ternary oxides, however very few studies have reported the performance of the binary Bi 2 O 3 which is the elementary constituent of the advanced bismuth mixed oxides. The photocatalytic behavior of the bismuth based oxides is well documented and the factors that limit their performance is well understood. Most importantly they exhibit low catalytic activity for oxygen evolution, which results in hole accumulation at the electrode/electrolyte interface. In order to overcome this limitation, a thin layer of oxygen evolution catalysts such as Co-Pi, FeOOH, Ni(OH) 2 or CoPO 4 is usually coated on the photoanodes.12-17 The binary and ternary bismuth oxides show more or less similar electronic structures, where the valence bands of both binary Bi 2 O 3 , and mixed bismuth oxides are considered to be formed by O-2p and Bi-6s orbitals. 18,19 The top of the Bi-6s orbital is positioned at more negative potential than that of O-2p. [20][21][22] The conduction band of Bi 2 O 3 is predominantly formed by Bi-6p orbitals. Whereas, the conduction band of mixed bismuth oxide is determined by the d-orbitals of transitions metals present in the mixed oxide. Bismuth oxide shows enhanced mobility of charge carriers because of its well-dispersed valence bands and it has high refractive index and large dielectric constant due to lone electron pairs of Bi(III) 6s 2 that...

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confidence: 94%

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting

Chitrada

Gakhar

Chidambaram

et al. 2016

J. Electrochem. Soc.

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“…Under visible light irradiation, the photogenered electron and hole is able to oxidize water. And, highly reactive species, such as O 2 •− and • OH radicals may be generated, which may act as initiators of oxidation reactions [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Photoelectrocatalytic degradation of organic contaminants at Bi2O3/TiO2 nanotube array electrode

Zhao

Liu

2011

Applied Surface Science

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a b s t r a c tIn the current work, TiO 2 nanotube array was prepared via electrochemical anode method. Then the Bi 2 O 3 nanoparticles were deposited onto the TiO 2 nanotube array via dip-coating method from an amorphous complex precursor. The crystal structures were characterized via X-ray diffraction analysis. Their surface textures were observed via electron-scanning microscope. The prepared composite array electrode exhibited high photoelectrocatalytic activities towards degrading organic contaminants under visible light irradiation. High photoelectrocatalytic activities were also exhibited under UV light irradiation. The catalytic mechanism was discussed based on the analysis of electrochemical and degradation kinetics results. It is suggested a P (Bi 2 O 3 )-N (TiO 2 ) junction was formed to increase the catalytic activates. The stability of the electrode materials was confirmed finally.

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“…Bismuth trioxide (Bi 2 O 3 ) is a semiconductor with interesting physical properties, such as a wide optical band-gap, high refractive index and dielectric permittivity, good photoconductive response, and ionic conductivity, which make this material suitable for applications in solid oxide fuel cells, gas sensing, optical coatings, catalysis, and optoelectronics. [1][2][3] phase is one of the best oxygen ion conductors known (r $ 1.5 S cm À1 ) and is considered as a reference material within the field of solid electrolytes. 6 This phase can be stabilized by addition of rare earth oxides, but the conductivity drops by about two orders of magnitude.…”

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confidence: 99%

“…SEM observations of both kinds of samples after irradiation revealed no morphological changes irrespective of the power density used or the exposure time to the laser beam. The development of the Bi 2 O 3 structural change was monitored in ceramics and nanowires by Raman spectroscopy, using laser power densities ranging from 10 5 to 10 2 W/cm 2 (Fig. 2).…”

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confidence: 99%

Laser irradiation-induced α to δ phase transformation in Bi2O3 ceramics and nanowires

2012

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Surface Phases and Photocatalytic Activity Correlation of Bi₂O₃/Bi₂O_4-x Nanocomposite

Abstract: UV-visible irradiation induces surface alteration of Bi2O3 leading to Bi2O3/Bi2O4-x nanocomposites with excellent photocatalytic activity.

Cited by 328 publications

References 7 publications

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting

Photoelectrocatalytic degradation of organic contaminants at Bi2O3/TiO2 nanotube array electrode

Laser irradiation-induced α to δ phase transformation in Bi2O3 ceramics and nanowires

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Surface Phases and Photocatalytic Activity Correlation of Bi2O3/Bi2O4-x Nanocomposite

Abstract: UV-visible irradiation induces surface alteration of Bi2O3 leading to Bi2O3/Bi2O4-x nanocomposites with excellent photocatalytic activity.

Cited by 328 publications

References 7 publications

Enhanced Performance of β-Bi2O3by In-Situ Photo-Conversion to Bi2O3-BiO2-xComposite Photoanode for Solar Water Splitting

Enhanced Performance of β-Bi2O3by In-Situ Photo-Conversion to Bi2O3-BiO2-xComposite Photoanode for Solar Water Splitting

Photoelectrocatalytic degradation of organic contaminants at Bi2O3/TiO2 nanotube array electrode

Laser irradiation-induced α to δ phase transformation in Bi2O3 ceramics and nanowires

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Surface Phases and Photocatalytic Activity Correlation of Bi₂O₃/Bi₂O_4-x Nanocomposite

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting

Enhanced Performance of β-Bi₂O₃by In-Situ Photo-Conversion to Bi₂O₃-BiO_2-xComposite Photoanode for Solar Water Splitting