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Nanostructured Pt Surfaces with Ir Submonolayers for Enhanced NH 3 Electro‐oxidation
Author(s) -
Fomedège Nzone,
Garbarino Sébastien,
Gaudet Julie,
Roué Lionel,
Guay Daniel
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600844
Subject(s) - iridium , platinum , adsorption , electrochemistry , surface modification , deposition (geology) , polarization (electrochemistry) , materials science , chemistry , analytical chemistry (journal) , electrode , inorganic chemistry , catalysis , organic chemistry , paleontology , sediment , biology
Preferentially (100)‐oriented nanostructured platinum films were modified by subsequent surface functionalization with iridium through pulsed electrodeposition. The Ir surface coverage was adjusted by varying the number of applied electrodeposition pulses, and was found to modify the reactivity towards NH 3 oxidation. Deposition of minute amount of Ir atoms ([Ir]=6 at%) at the surface of preferentially (100)‐oriented Pt leads to a decrease in the NH 3 oxidation onset potential (from −430 to −500 mV vs. Hg/HgO), an increase in the current density (at −0.30 V) from 0.55 to 0.67 mA cm −2 , and an increase in the poisoning resistance over polarization at constant potential. This is attributed to the preferential adsorption of Ir atoms at Pt(100) step sites close to the Pt(100) terraces that are known to be the more active for the electro‐oxidation of NH 3 .