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Visible‐Light‐Induced Electron Transport from Small to Large Nanoparticles in Bimodal Gold Nanoparticle‐Loaded Titanium(IV) Oxide
Author(s) -
Naya Shinichi,
Niwa Tadahiro,
Kume Takahiro,
Tada Hiroaki
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201402939
Subject(s) - surface plasmon resonance , nanoparticle , visible spectrum , photocatalysis , materials science , colloidal gold , photochemistry , oxide , titanium , titanium oxide , nanotechnology , chemical engineering , chemistry , optoelectronics , catalysis , organic chemistry , engineering , metallurgy
A key to realizing the sustainable society is to develop highly active photocatalysts for selective organic synthesis effectively using sunlight as the energy source. Recently, metal‐oxide‐supported gold nanoparticles (NPs) have emerged as a new type of visible‐light photocatalysts driven by the excitation of localized surface plasmon resonance of Au NPs. Here we show that visible‐light irradiation ( λ >430 nm) of TiO 2 ‐supported Au NPs with a bimodal size distribution (BM‐Au/TiO 2 ) gives rise to the long‐range (>40 nm) electron transport from about 14 small (ca. 2 nm) Au NPs to one large (ca. 9 nm) Au NP through the conduction band of TiO 2 . As a result of the enhancement of charge separation, BM‐Au/TiO 2 exhibits a high level of visible‐light activity for the one‐step synthesis of azobenzenes from nitrobenzenes at 25 °C with a yield greater than 95 % and a selectivity greater than 99 %, whereas unimodal Au/TiO 2 (UM‐Au/TiO 2 ) is photocatalytically inactive.