Water Reduction Photocathodes Based on Ru Complex Dyes Covered with a Conjugated Polymer Nanosheet

Taku Shimamura, Atsushi Kobayashi, Yuya Oaki, Masaki Yoshida, Masako Kato

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Water-splitting dye-sensitized photoelectrochemical cells are promising devices for resolving energy and environmental problems by producing H2, a clean energy source, from water and sunlight. However, their performance is still limited because of dye desorption from the electrode and their weak light-absorption efficiency. In this study, we fabricated two water-reducing photocathodes, NiO|RuCP/BQPy and NiO|RuCP-Zr-RuP/BQPy, by combining the layer-by-layer formation of mono- (RuCP) and bi- (RuCP and RuP with Zr4+cations) layer molecular films of Ru(II) dyes, respectively, on a p-type NiO substrate with the chemical vapor deposition of the nanosheet catalyst based on the BQPy organic polymer comprising benzoquinone and pyrrole moieties. These photocathodes produced H2under visible light irradiation and a small electrical bias in a 0.1 M Na2SO4aqueous solution (λ > 420 nm, 65 mW cm-2, E = -0.254 V versus normal hydrogen electrode, and pH 3). Both the photocurrent value and amount of H2produced by double-dye-layered NiO|RuCP-Zr-RuP/BQPy were smaller than those of NiO|RuCP/BQPy, probably because of the energy transfer inactivation between the Ru(II) dyes, which competes with the reductive quenching (i.e., electron injection) by NiO. Ru(II) dye desorption from the NiO|RuCP/BQPy photocathode was significantly reduced to approximately a third of that of NiO|RuCP, indicating that the deposited BQPy polymer improved the durability of the photocathode. The deposition of the BQPy polymer can be easily performed under mild conditions (60 °C in air); therefore, this technique shows great potential application for the construction of various types of dye-sensitized water-reducing photocathodes.

Original languageEnglish
Pages (from-to)11559-11566
Number of pages8
JournalEnergy and Fuels
Issue number19
Publication statusPublished - 2022 Oct 6

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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