In situ structural characterization of platinum dendrimer-encapsulated oxygen reduction electrocatalysts.
In situ electrochemical extended X-ray absorption fine structure (EXAFS) was used to evaluate the structure of Pt dendrimer-encapsulated nanoparticles (DENs) during the oxygen reduction reaction (ORR). The DENs contained an average of just 225 atoms each. The results indicate that the Pt coordination number (CN) decreases when the electrode potential is moved to positive values. The results are interpreted in terms of an ordered core, disordered shell model. The structure of the DENs is not significantly impacted by the presence of dioxygen, but other electrogenerated species may have a significant impact on nanoparticle structure.
Department of Chemistry and Biochemistry, Center for Electrochemistry, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, 1 University Station, A5300, Austin, Texas 78712-0165, USA.
V Sue
VS
Myers
Anatoly I
AI
Frenkel
Richard M
RM
Crooks