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Dealloying and Synthesis of Nanoporous Pt and Au from AgPt and AgAu Binary Alloys

A study is presented on the synthesis and characterization of nanoporous AgPt and AgAu
alloys after annealing and dealloying in 5% HClO4. Dealloying removes the less-noble atom
from the alloy surface to produce nanoporous, highly-interconnected ligaments. Voltammetry of AgPt and AgAu shows the critical potential, Ec, at various potential scan rates. Potential hold current decay experiments on Ag-23Pt and Ag-23Au further show the intrinsic Ec to be 275 mV and 290 mV, respectively. Ec was governed by thermodynamic clustering in the alloys as
opposed to dissolution-diffusion kinetic effects. EDX shows the starting 77Ag-23Pt material changes composition after dealloying to about 12Ag-88Pt. XRD indicates the presence of ordering in AgPt via a superlattice (100)-peak for a specific anneal treatment. EIS measurements done on as-annealed and dealloyed AgPt and AgAu samples show the onset of bulk porosity and show that capacitance increase is equal for both alloys at two different dealloying potentials.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/25594
Date31 December 2010
CreatorsGanti Mahapatruni, Aditya
ContributorsNewman, Roger C.
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
Languageen_ca
Detected LanguageEnglish
TypeThesis

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