Photocatalytic activity of hydrothermally synthesized tantalate pyrochlores for overall water splitting

Ikeda, Shigeru; Fubuki, Minori; Takahara, Yoshiko; Matsumura, Michio

doi:10.1016/j.apcata.2005.11.007

Cited by 111 publications

(70 citation statements)

References 19 publications

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“…ZnS, 13,16,18,19 niobates, [20][21][22][23][24] and tantalates [25][26][27][28] ) have been examined as photocatalysts for hydrogen production from splitting water. However, the majority of the simple and mixed-metal oxides photocatalysts are primarily active for H 2 production under UV irradiation (l < 385 nm or E g $ 3.0 eV) present in only a small portion of solar light.…”

Section: -17mentioning

confidence: 99%

Photocatalytic production of hydrogen on Ni/NiO/KNbO3/CdS nanocomposites using visible light

et al. 2008

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3. Enhanced activity is most likely due to effective charge separation of photogenerated electrons and holes in CdS that is achieved by electron injection into the conduction band of KNbO 3 and the reduced states of niobium (e.g., Nb(IV) and Nb(III)) are shown to contribute to enhanced reactivity in the KNbO 3 composites by mediating effective electron transfer to bound protons. We also observed that the efficient attachment of Q-size CdS and the deposition of nickel on the KNbO 3 surface increases H 2 production rates. Other factors that influence the rate of H 2 production including the nature of the electron donors and the solution pH were also determined. The Ni/NiO/KNbO 3 /CdS nanocomposite system appears to be a promising candidate for possible practical applications including the production of H 2 under visible light.

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Section: -17mentioning

confidence: 99%

Photocatalytic production of hydrogen on Ni/NiO/KNbO3/CdS nanocomposites using visible light

et al. 2008

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“…Their band gap can be easily tuned by introduction of metal ions [8], since the structure has a high tolerance for impurities. A few pyrochlores such as metal doped Ca 2 Ta 2 O 7 [9], InTaO 4 [10], CsTaWO 6 [11], AgBiNb 2 O 7 [12], Cd 2 Ta 2 O 7 [13], Bi 2 GaNbO 7 [14] and Y 2 Ti 2 O 7 [15] have been found to be active for overall water splitting.…”

Section: Introductionmentioning

confidence: 97%

Active Sites for Light Driven Proton Reduction in Y2Ti2O7 and CsTaWO6 Pyrochlore Catalysts Detected by In Situ EPR

et al. 2015

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In situ EPR spectroscopy proved to be a versatile tool to identify active sites for photocatalytic hydrogen generation in modified Y 2 Ti 2 O 7 and CsTaWO 6 catalysts of pyrochlore structure, in which the metal cations are located in two different positions A and B. It was found that the B-sites exclusively occupied by titanium (Y 2 Ti 2 O 7 ) and tantalum/tungsten (CsTaWO 6 ) act as electron traps on the surface. From these sites, electron transfer to the cocatalysts proceeds. Thus, the B-sites are responsible for photocatalytic water reduction. Graphical Abstract

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“…Firstly, K 2 Ta 2 O 6 was fabricated from a tantalum sheet by a hydrothermal synthesize with KOH (Kanto Chemical Co. INC., Cica-Reagent, 86.0%) aqueous (deionized water) solution [6][7][8][9][10]. The starting materials for the hydrothermal synthesis were Ta (Nilaco, 99.95%) and KOH.…”

Section: Methodsmentioning

confidence: 99%

Ion-Exchange Reaction Of A-Site In A2Ta2O6 Pyrochlore Crystal Structure

Matsunami¹,

Hashizume²,

Saiki³

2015

Archives of Metallurgy and Materials

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Na + or K + ion rechargeable battery is started to garner attention recently in Place of Li+ ion cell. It is important that A+ site ion can move in and out the positive-electrode materials. When K 2 Ta 2 O 6 powder had a pyrochlore structure was only dipped into NaOH aqueous solution at room temperature, Na 2 Ta 2 O 6 was obtained. K 2 Ta 2 O 6 was fabricated from a tantalum sheet by a hydrothermal synthesize with KOH aqueous solution. When Na 2 Ta 2 O 6 was dipped into KOH aqueous solution, K 2 Ta 2 O 6 was obtained again. If KTaO 3 had a perovskite structure was dipped, Ion-exchange was not observed by XRD. Because a lattice constant of pyrochlore structure of K-Ta-O system is bigger than perovskite, K + or Na + ion could shinny through and exchange between Ta 5+ and O 2− ion site in a pyrochlore structure. K + or Na + ion exchange of A 2 Ta 2 O 6 pyrochlore had reversibility. Therefore, A 2 Ta 2 O 6 had a pyrochlore structure can be expected such as Na + ion rechargeable battery element.Keywords: K 2 Ta 2 O 6, Na 2 Ta 2 O 6, Ion-exchange, pyrochlore structure, perovskite structure Akumulatory w którym jako nośniki ładunku wykorzystywane są jony Na + lub K + budzą coraz większe zainteresowanie jako alternatywa dla ogniw litowo-jonowych. Należy podkreślić, że kationy w podsieci A + potrafią się przemieszczać z-i do dodatnio naładowanych materiałów elektrodowych. Gdy proszek K 2 Ta 2 O 6 posiadający strukturę pirochloru zanurzono w roztworze wodnym NaOH w temperaturze pokojowej, otrzymano Na 2 Ta 2 O 6 . K 2 Ta 2 O 6 otrzymano poprzez obróbkę arkuszu tantalu metodą hydrotermalną wykorzystując roztwór wodny KOH. Gdy zanurzono Na 2 Ta 2 O 6 w wodnym roztworze KOH, otrzymano z powrotem K 2 Ta 2 O 6 . Natomiast, gdy zanurzono KTaO 3 o strukturze perowskitu, nie obserwowano wymiany jonowej. Dlatego, że stała sieciowa w strukturze pirochloru układu K-Ta-O jest większa niż w przypadku perowskitu, jony K + lub Na + mogą się poruszać i wymieniać w podsieci Ta 5+ i O 2− w pirochlorze. Wymiana jonów K + lub Na + w pirochlorze A 2 Ta 2 O 6 jest odwracalna. Z tego powodu można się spodziewać, że związek A 2 Ta 2 O 6 o strukturze pirochloru może znaleźć potencjalne zastosowanie jako element akumulatora pracującego z jonami Na + .

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Photocatalytic activity of hydrothermally synthesized tantalate pyrochlores for overall water splitting

Cited by 111 publications

References 19 publications

Photocatalytic production of hydrogen on Ni/NiO/KNbO3/CdS nanocomposites using visible light

Photocatalytic production of hydrogen on Ni/NiO/KNbO3/CdS nanocomposites using visible light

Active Sites for Light Driven Proton Reduction in Y2Ti2O7 and CsTaWO6 Pyrochlore Catalysts Detected by In Situ EPR

Ion-Exchange Reaction Of A-Site In A2Ta2O6 Pyrochlore Crystal Structure

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