“…Previously, in situ EQCM technique based on estimation (the differential frequency response) [1,2] of the so-called apparent equivalent molar mass (k) per second has been proved to be very powerful in elucidating electrode reaction processes accompanying a mass change during potential-scan electrolysis in aqueous, organic media and RTILs [3,[4][5][6][7][8]. Here, the size and morphology of Au particles and relative ratio of its crystalline orientation domains on Pt, Au, and carbon electrodes have been found to largely depend on the electrolysis potential used in the electro-deposition, that is, on whether [AuCl 2 ] À species is present or not [11,12].…”