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Formation of Nanostructured Gold Sponges by Anodic Dealloying. EIS Investigation of Product and Process
Author(s) -
Cattarin S.,
Kramer D.,
Lui A.,
Musiani M.
Publication year - 2009
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.200800075
Subject(s) - dissolution , materials science , leaching (pedology) , anode , chemical engineering , metal , porosity , alloy , faraday efficiency , capacitive sensing , metallurgy , nanotechnology , composite material , electrode , chemistry , computer science , environmental science , soil science , engineering , soil water , operating system
Gold sponges are prepared by anodic leaching of silver from Ag 75 Au 25 alloy sheets in 1 mol L —1 HClO 4 solutions. EIS investigations performed after exhaustive dissolution, under blocking conditions, show classical porous behaviour and a capacity, increasing with dissolution potential, in the range of 3–10 F g —1 . The observed time decrease of capacity is consistent with the occurrence of slow coarsening phenomena. EIS investigations performed during dissolution show a faradaic process in parallel with capacitive charging of the metal sponge, and a much larger capacity. The phenomena are discussed and a simulation is presented, based on a set of plausible parameters.