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Activation/Inhibition Effects during the Coelectrodeposition of PtAg Nanoparticles: Application for ORR in Alkaline Media
Author(s) -
Schwamborn Stefanie,
Stoica Leonard,
Schuhmann Wolfgang
Publication year - 2011
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201100029
Subject(s) - bimetallic strip , nanoparticle , alloy , chemistry , ion , oxygen reduction reaction , diffusion , deposition (geology) , shell (structure) , inorganic chemistry , chemical engineering , nanotechnology , materials science , catalysis , electrochemistry , organic chemistry , electrode , thermodynamics , paleontology , physics , sediment , biology , engineering , composite material
PtAg bimetallic nanoparticles for oxygen reduction reaction (ORR) in alkaline media were prepared by pulse electrodeposition (PED). During PED the reduction of Ag + ions predominates, thus an increased Ag content in the co‐deposit is accomplished. The mechanism for this anomalous co‐deposition was elucidated by potential pulse experiments, which revealed that nuclei formation mainly occurs via the reduction of Pt 2+ ions. The growth of the particles is diffusion controlled leading to the formation of a Ag shell covering a PtAg alloyed region. However, the shell is not growing homogeneously on the PtAg alloy. Hence, regions of the PtAg alloy are exposed, which exhibit an enhanced ORR activity compared to a pure Ag surface.