Photocatalytic Reduction of Ag2SO4 by Dawson-Derived Sandwich Complex |
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Authors: | Laurent Ruhlmann Claire Costa-Coquelard Sébastien Sorgues Isabelle Lampre |
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Institution: | Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud 11, Faculté des Sciences d'Orsay, Bâtiment 349, 91405 Orsay Cedex, France |
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Abstract: | Photocatalytic reduction of AgI2SO4 from aqueous solutions is observed in the presence of Dawson-derived sandwich type polyoxometalates (POMs) M4(P2W15O56)2]16?, M = Co2+, Ni2+ and Zn2+ 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 Ag0 metal atoms which then form by aggregation colloidal metal nanoparticles stabilized by POM. In the case of Co4(P2W15O56)2]16?, TEM experiments reveal that the Agn 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. |
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Keywords: | dawson photocatalysis polyoxometalates |
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