The films were built upon gold electrode substrates, both gold quartz crystal electrodes and bulk gold (Au(bulk)) electrodes, and formation of the LBL films was gravimetrically monitored by an electrochemical quartz crystal microbalance.
From the measured R s and effective layer thickness, layer resistivity R (ohm centimeter) was calculated, which appears to be orders of magnitude higher than that reported for metallic bulk gold (R Au bulk = 2.5 × 10−6 Ω cm [21], e.g., for 100-nm thick Au layer R Au 100 nm = 1 × 10−3 Ω cm).
Indeed, gold in bulk state is chemically inert since the redox potential of this noble metal is positive [15].
For instance, gold in bulk form is inert and conducts electricity, however gold shrunk into "nano" form becomes a very good catalyst and turns into a semiconductor instead.
Despite the inertia of bulk gold and of extended gold surfaces towards oxygen, gold-oxide nanocomposites were found, at the end of the 20th Century, to display exceptional low temperature catalytic activity in oxidation reactions, based on a concerted mechanism involving support-mediated oxygen activation.
(A) TEM images at (a) 0.5 mM KAuCl4, abundance of spheres; (b) 1 mM KAuCl4, abundance of spheres; (c) 1.5 mM KAuCl4, formation tending to bulk gold; and (d) 2 mM KAuCl4, bulk gold [Reaction conditions: 1 mL YFLE, pH 4.2, and 22°C to 24°C temperature].
While bulk gold is shiny, golden in color, inert, and conducts electricity, nano-sized gold particles with a diameter of 10 nm are red in color, catalytically active and semi-conductive [ 3].
These Au particles exhibit the 4f binding energies that are characteristics for the bulk gold.
Although the British administration built roads connecting its sphere with the road system of the Gold Coast, the bulk of the territory's external trade passed over the railways of French Togo.
For example, in bulk gold is typically inert.
