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Light‐Harvesting Photocatalysis for Water Oxidation Using Mesoporous Organosilica
Author(s) -
Takeda Hiroyuki,
Ohashi Masataka,
Goto Yasutomo,
Ohsuna Tetsu,
Tani Takao,
Inagaki Shinji
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302815
Subject(s) - photochemistry , photocatalysis , visible spectrum , mesoporous material , iridium , chemistry , photosensitizer , mesoporous organosilica , quantum yield , oxygen evolution , solar fuel , water splitting , catalysis , photosystem ii , electron transfer , materials science , fluorescence , electrochemistry , photosynthesis , optoelectronics , organic chemistry , mesoporous silica , biochemistry , physics , electrode , quantum mechanics
An organic‐based photocatalysis system for water oxidation, with visible‐light harvesting antennae, was constructed using periodic mesoporous organosilica (PMO). PMO containing acridone groups in the framework (Acd‐PMO), a visible‐light harvesting antenna, was supported with [Ru II (bpy) 3 2+ ] complex (bpy=2,2′‐bipyridyl) coupled with iridium oxide (IrO x ) particles in the mesochannels as photosensitizer and catalyst, respectively. Acd‐PMO absorbed visible light and funneled the light energy into the Ru complex in the mesochannels through excitation energy transfer. The excited state of Ru complex is oxidatively quenched by a sacrificial oxidant (Na 2 S 2 O 8 ) to form Ru 3+ species. The Ru 3+ species extracts an electron from IrO x to oxidize water for oxygen production. The reaction quantum yield was 0.34 %, which was improved to 0.68 or 1.2 % by the modifications of PMO. A unique sequence of reactions mimicking natural photosystem II, 1) light‐harvesting, 2) charge separation, and 3) oxygen generation, were realized for the first time by using the light‐harvesting PMO.