Spontaneous Deposition of Ru on Au

Once the saturation coverage of Ru on Au(lll) had been achieved, it was possible to increase it further using a multiple spontaneous deposition method.17 After the first deposition, the crystal was held at 0.1 V in H2SO4 to reduce Ru oxide, then the solution was replaced at the OCP with a ruthenium-containing solution and the deposition was performed for another 3 min, without removal of the deposited ruthenium from the previous deposition. STM images obtained after three consecutive depositions of 3 min each are shown in Fig. 8c, d.16 An increase in the number of Ru islands 

The step decoration obtained during spontaneous deposition of Ru on the Au(l 11) surface indicates that the steps were the active sites for the chemical reactions involving the formation of solid Ru02 species and subsequent chemical disproportionate reaction discussed above. This reveals that, for a particular concentration of the solution, the density of the steps is the main factor determining the Ru coverage. A higher density of steps or active sites can be achieved either by multiple deposition, whereby the deposited Ru islands take over the role of active sites in the deposition (see 

On the smaller scale STM images (Fig. 10) the hexagonal shape of the Ru islands and their uniformity in size are clearly resolved. Moreover, the islands are regularly arranged one beside another 

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