TY - JOUR
T1 - Role of iron ion electron mediator on photocatalytic Overall water splitting under visible light irradiation using Z-scheme systems
AU - Kato, Hideki
AU - Sasaki, Yasuyoshi
AU - Iwase, Akihide
AU - Kudo, Akihiko
PY - 2007
Y1 - 2007
N2 - 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.
AB - 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.
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U2 - 10.1246/bcsj.80.2457
DO - 10.1246/bcsj.80.2457
M3 - Article
AN - SCOPUS:51349105952
SN - 0009-2673
VL - 80
SP - 2457
EP - 2464
JO - Bulletin of the Chemical Society of Japan
JF - Bulletin of the Chemical Society of Japan
IS - 12
ER -
