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Electrochemical Cleaning Stability and Oxygen Reduction Reaction Activity of 1‐2 nm Dendrimer‐Encapsulated Au Nanoparticles
Author(s) -
Strasser Juliette W.,
Hersbach Thomas J. P.,
Liu Jing,
Lapp Aliya S.,
Frenkel Anatoly I.,
Crooks Richard M.
Publication year - 2021
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202100549
Subject(s) - dendrimer , electrochemistry , transmission electron microscopy , amine gas treating , nanoparticle , absorption spectroscopy , x ray absorption spectroscopy , chemistry , absorption (acoustics) , materials science , crystallography , analytical chemistry (journal) , nanotechnology , nuclear chemistry , electrode , polymer chemistry , organic chemistry , quantum mechanics , composite material , physics
Here we show that just three electrochemical scans to modest positive potentials result in substantial growth of 1–2 nm Au dendrimer‐encapsulated nanoparticles (DENs). We examined two sizes of Au DENs, denoted as G6‐NH 2 (Au 147 ) and G6‐NH 2 (Au 55 ), where G6‐NH 2 represents a sixth‐generation, amine‐terminated, poly(amidoamine) dendrimer and the subscripts, 147 and 55, represent the average number of atoms in each size of DENs. Ex situ transmission electron microscopy (TEM) and in situ X‐ray absorption spectroscopy (XAS) results indicate that G6‐NH 2 (Au 55 ) DENs grow to the same size as the G6‐NH 2 (Au 147 ) DENs following these scans. Importantly, this growth occurs prior to the onset of detectable faradaic Au oxidation or reduction current. The observed growth in the size of the DENs directly correlates to changes in the electrocatalytic ORR activity. The key point is that after just three positive scans the G6‐NH 2 (Au 147 ) and G6‐NH 2 (Au 55 ) DENs are essentially indistinguishable in terms of both physical and electrocatalytic properties.