Role of iron ion electron mediator on photocatalytic Overall water splitting under visible light irradiation using Z-scheme systems

Hideki Kato, Yasuyoshi Sasaki, Akihide Iwase, Akihiko Kudo

Research output: Contribution to journalArticlepeer-review

111 Citations (Scopus)

Abstract

A combination system consisting of a H2 production photocatalyst, Pt/SrTiO3:Rh, and an O2 production photo-catalyst, BiVO4 or WO3, decomposed water into H 2 and O2 under visible light irradiation in the presence of an Fe3+/Fe2+ redox couple as an electron mediator. O2 evolution on the BiVO4 photocatalyst was inhibited by Fe2+ ions, because of the oxidation of Fe2+ instead of water. In contrast, H2 evolution on the Pt/SrTiO3:Rh photocatalyst was enhanced when Fe3+ ions co-existed. It is due to the back-reactions between H2 and O2 to form water, and the reduction of Fe3+ by H2, which easily proceeded on the bare Pt cocatalyst surface, being efficiently suppressed by adsorption of [Fe(SO4)(H2O)5]+ and/or [Fe(OH)(H2O)5]2+ on the Pt surface. Overall water splitting was achieved with the suppression of the back-reactions even using a Pt cocatalyst. Thus, it clears that iron ions contributed to the present Z-scheme systems not only as an electron mediator but also as an inhibitor of the back-reactions.

Original languageEnglish
Pages (from-to)2457-2464
Number of pages8
JournalBulletin of the Chemical Society of Japan
Volume80
Issue number12
DOIs
Publication statusPublished - 2007 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)

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