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Photocatalytic Reduction of Ag 2 SO 4 by Dawson‐Derived Sandwich Complex
Author(s) -
Ruhlmann Laurent,
CostaCoquelard Claire,
Sorgues Sébastien,
Lampre Isabelle
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200851014
Subject(s) - photocatalysis , aqueous solution , electron transfer , metal , colloid , materials science , ion , nanoparticle , photochemistry , metal ions in aqueous solution , polyoxometalate , chemical engineering , chemistry , nanotechnology , catalysis , organic chemistry , metallurgy , engineering
Photocatalytic reduction of Ag I 2 SO 4 from aqueous solutions is observed in the presence of Dawson‐derived sandwich type polyoxometalates (POMs) [M 4 (P 2 W 15 O 56 ) 2 ] 16− , M = Co 2+ , Ni 2+ and Zn 2+ as photocatalyst and an organic substrate (propan‐2‐ol) as sacrificial electron donor. The direct photochemical excitation of the Dawson‐derived sandwich type polyoxometalates in the presence of propan‐2‐ol leads to its reduction. That first reduction step induces electron transfer to Ag + ions to give Ag 0 metal atoms which then form by aggregation colloidal metal nanoparticles stabilized by POM. In the case of [Co 4 (P 2 W 15 O 56 ) 2 ] 16− , TEM experiments reveal that the Ag n particles obtained with a slight excess of Ag + are almost spherical with size in the range 20 – 50 nm. However, in a large excess of Ag + , the obtained colloids are more oblate and assembled together to give larger aggregates.