Abstract:
The surfaces of nanoscale gold particles and
components are oxide-free under normal ambient
conditions. This unusual attribute permits the
exploration of microstructures and functionalities that
would not be feasible for less noble metals. Here we
consider the electrochemical properties of
mesoporous gold sponges, prepared by de-alloying an
AuAl2 precursor. The sponges have a high specific
surface area, with an average pore diameter of 12 nm,
but are prone to sinter. They may be prepared in bulk,
or, more usefully, as coatings. Their electrochemical
capacitance divided by their nominal surface area is
high and, at a cell voltage of 0.6 V, reaches 100 mF/cm2
for bulk samples and 2 mF/cm2 for coatings. This is up
to a thousand times greater than the 50 to 100 μF/cm2
exhibited by a planar gold surface.
