可視光に応答する水の完全分解光触媒の設計と創製  [in Japanese] Designs and Preparations of Visible-Light-Sensitive Overall Water-Splitting Photocatalysts  [in Japanese]

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Author(s)

    • 入江 寛 IRIE Hiroshi
    • 山梨大学 クリーンエネルギー研究センター|(独)科学技術振興機構CREST Japan Science and Technology Agency (JST)|Core Research for Evolutionary Science and Technology (CREST)

Abstract

粉末光触媒を用いた可視光照射下での水の完全分解に関する既往の研究は一段階励起,二段階励起による分解の二つに区分される。 それらを概説したのち,それらを参考に,また違った観点から,可視光照射下で純水の完全分解が可能な光触媒創製を試みた。一段階励起ではタンタル酸銀のタンタルサイトをニオブ置換(AgTa<sub>0.7</sub>Nb<sub>0.3</sub>O<sub>3</sub>)により伝導帯下端を正の電位シフトすることによって可視光での純水の完全分解を達成した。また二段階励起では銀を酸化還元対および接着剤として用い,水素発生光触媒としてのロジウム酸亜鉛,酸素発生光触媒としてのアンチモン酸銀を接合することによって全固体型二段階励起光触媒ZnRh<sub>2</sub>O<sub>4</sub>/Ag/Ag<sub>1−<i>x</i></sub>SbO<sub>3­−<i>y</i></sub>を創製した。この二段階励起光触媒は可視光照射下で純水を完全分解できた。後者の方法はさまざまな水素・酸素発生光触媒に適用可能であり,現状,波長600 nmまでの可視光を利用して純水の完全分解に成功している。

Visible-light-sensitive overall water-splitting powdered photocatalysts can be classified into two types; one is a one-step excitation system using one photocatalyst and the other is a two-step excitation system consisting of two types of photocatalysts with a suitable redox mediator. Based on suggestions made in the literature regarding the one-step and two-step excitation systems, we investigated novel photocatalysts to split pure water under visible light. As for the one-step system, visible-light-induced pure water splitting was achieved by increasing the visible-light sensitivity of silver tantalate (AgTaO<sub>3</sub>), by the introduction of niobium (Nb) to shift the bottom of conduction band (CB) downwards, generating AgTa<sub>0.7</sub>Nb<sub>0.3</sub>O<sub>3</sub>. As for the two-step system, zinc rhodium oxide (ZnRh<sub>2</sub>O<sub>4</sub>) and defective silver antimonate (Ag<sub>1-<i>x</i></sub>SbO<sub>3-<i>y</i></sub>) as hydrogen (H<sub>2</sub>)- and oxygen (O<sub>2</sub>)-evolution photocatalysts, respectively, were connected with silver (Ag) as a glue to prepare an all solid-state two-step photocatalysis system (ZnRh<sub>2</sub>O<sub>4</sub>/Ag/Ag<sub>1-<i>x</i></sub>SbO<sub>3-<i>y</i></sub>). In this system, Ag acted as a solid-state electron mediator for the transfer of electrons from the CB of Ag<sub>1-<i>x</i></sub>SbO<sub>3-<i>y</i></sub> to the valence band of ZnRh<sub>2</sub>O<sub>4</sub>. Utilizing the ZnRh<sub>2</sub>O<sub>4</sub>/Ag/Ag<sub>1-<i>x</i></sub>SbO<sub>3-<i>y</i></sub> photocatalyst, we could achieve overall pure water-splitting under irradiation with visible light.

Journal

  • Journal of the Japan Society of Colour Material

    Journal of the Japan Society of Colour Material 88(1), 8-12, 2015

    Japan Society of Colour Material

Codes

  • NII Article ID (NAID)
    130005064861
  • NII NACSIS-CAT ID (NCID)
    AN00354634
  • Text Lang
    JPN
  • ISSN
    0010-180X
  • NDL Article ID
    026050973
  • NDL Call No.
    Z17-211
  • Data Source
    NDL  J-STAGE 
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