Photoanodic and photocathodic behaviour of La5Ti2CuS5O7 electrodes in the water splitting reaction

Guijun Ma; Yohichi Suzuki; Rupashree Balia Singh; Aki Iwanaga; Yosuke Moriya; Tsutomu Minegishi; Jingyuan Liu; Takashi Hisatomi; Hiroshi Nishiyama; Masao Katayama; Kazuhiko Seki; Akihiro Furube; Taro Yamada; Kazunari Domen

doi:10.1039/c5sc01344e

Photoanodic and photocathodic behaviour of La₅Ti₂CuS₅O₇ electrodes in the water splitting reaction

Chem Sci. 2015 Aug 1;6(8):4513-4518. doi: 10.1039/c5sc01344e. Epub 2015 Jun 11.

Authors

Guijun Ma^{1

2}, Yohichi Suzuki^{1

3}, Rupashree Balia Singh³, Aki Iwanaga¹, Yosuke Moriya^{1

2}, Tsutomu Minegishi^{1

2}, Jingyuan Liu¹, Takashi Hisatomi^{1

2}, Hiroshi Nishiyama^{2

4}, Masao Katayama^{1

2}, Kazuhiko Seki³, Akihiro Furube³, Taro Yamada^{2

4}, Kazunari Domen^{1

2}

Affiliations

¹ Department of Chemical System Engineering , The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku , Tokyo 113-8656 , Japan . Email: domen@chemsys.t.u-tokyo.ac.jp ; ; Tel: +81-3-5841-1148.
² Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem) , 5-1-5 Kashiwanoha , Kashiwa-shi , Chiba 277-8589 , Japan.
³ National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8565 , Japan.
⁴ Department of Chemical System Engineering , The University of Tokyo , 5-1-5 Kashiwanoha , Kashiwa-shi , Chiba 277-8589 , Japan.

Abstract

The particulate semiconductor La₅Ti₂CuS₅O₇ (LTC) with a band gap energy of 1.9 eV functioned as either a photocathode or a photoanode when embedded onto Au or Ti metal layers, respectively. By applying an LTC/Au photocathode and LTC/Ti photoanode to, respectively, photoelectrochemical (PEC) water reduction and oxidation concurrently, zero-bias overall water splitting was accomplished under visible light irradiation. The band structures of LTC/Au and LTC/Ti calculated using a semiconductor device simulator (AFORS-HET) confirmed the critical role of the solid/solid junction of the metal back contact in the charge separation and PEC properties of LTC photoelectrodes. The prominently long lifetime of photoexcited charge carriers in LTC, confirmed by transient absorption spectroscopy, allowed the utilization of both photoexcited electrons and holes depending on the band structure at the solid/solid junction.