Document Detail

Hydrophilicity Control of Visible-Light Hydrogen Evolution and Dynamics of the Charge-Separated State in Dye/TiO(2) /Pt Hybrid Systems.
MedLine Citation:
PMID:  23042083     Owner:  NLM     Status:  Publisher    
Visible-light-driven H(2) evolution based on Dye/TiO(2) /Pt hybrid photocatalysts was investigated for a series of (E)-3-(5'-{4-[bis(4-R(1) -phenyl)amino]phenyl}-4,4'-(R(2) )(2) -2,2'-bithiophen-5-yl)-2-cyanoacrylic acid dyes. Efficiencies of hydrogen evolution from aqueous suspensions in the presence of ethylenediaminetetraacetic acid as electron donor under illumination at λ>420 nm were found to considerably depend on the hydrophilic character of R(1) , varying in the order MOD (R(1) =CH(3) OCH(2) , R(2) =H)≈MO4D (R(1) =R(2) =CH(3) OCH(2) )>HD (R(1) =R(2) =H)>PD (R(1) =C(3) H(7) , R(2) =H). In the case of MOD/TiO(2) /Pt, the apparent quantum yield for photocatalyzed H(2) generation at 436 nm was 0.27±0.03. Transient absorption measurements for MOD- or PD-grafted transparent films of TiO(2) nanoparticles dipped into water at pH 3 commonly revealed ultrafast formation (<100 fs) of the dye radical cation (Dye(.) (+) ) followed by multicomponent decays, which involve minor fast decays (<5 ps) almost independent of R(1) and major slower decays with significant differences between the two samples: 1) the early decay of the major components for MOD is about 2.5 times slower than that for PD and 2) a redshift of the spectrum occurred for MOD with a time constant of 17 ps, but not for PD. The substituent effects on H(2) generation as well as on transient behavior have been discussed in terms substituent-dependent charge recombination (CR) of Dye(.) (+) with electrons in bulk, inner-trap, and/or interstitial-trap states, arising from different solvent reorganization.
Won-Sik Han; Kyung-Ryang Wee; Hyun-Young Kim; Chyongjin Pac; Yu Nabetani; Daisuke Yamamoto; Tetsuya Shimada; Haruo Inoue; Heesung Choi; Kyeongjae Cho; Sang Ook Kang
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-5
Journal Detail:
Title:  Chemistry (Weinheim an der Bergstrasse, Germany)     Volume:  -     ISSN:  1521-3765     ISO Abbreviation:  Chemistry     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9513783     Medline TA:  Chemistry     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Department of Advanced Materials Chemistry, Sejong, Korea University, 208 Seochang, Chochiwon, Chung-nam 339-700 (Korea), Fax: (+82) 44-867-5396.
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