posted on 2020-04-27, 14:34authored byTakayoshi Oshima, Shunta Nishioka, Yuka Kikuchi, Shota Hirai, Kei-ichi Yanagisawa, Miharu Eguchi, Yugo Miseki, Toshiyuki Yokoi, Tatsuto Yui, Koji Kimoto, Kazuhiro Sayama, Osamu Ishitani, Thomas E. Mallouk, Kazuhiko Maeda
Sensitization
of a wide-gap oxide semiconductor with a visible-light-absorbing
dye has been studied for decades as a means of producing H2 from water. However, efficient overall water splitting using a dye-sensitized
oxide photocatalyst has remained an unmet challenge. Here we demonstrate
visible-light-driven overall water splitting into H2 and
O2 using HCa2Nb3O10 nanosheets
sensitized by a Ru(II) tris-diimine type photosensitizer, in combination
with a WO3-based water oxidation photocatalyst and a triiodide/iodide
redox couple. With the use of Pt-intercalated HCa2Nb3O10 nanosheets further modified with amorphous
Al2O3 clusters as the H2 evolution
component, the dye-based turnover number and frequency for H2 evolution reached 4580 and 1960 h–1, respectively.
The apparent quantum yield for overall water splitting using 420 nm
light was 2.4%, by far the highest among dye-sensitized overall water
splitting systems reported to date. The present work clearly shows
that a carefully designed dye/oxide hybrid has great potential for
photocatalytic H2 production, and represents a significant
leap forward in the development of solar-driven water splitting systems.