The change in the area and catalytic activity of metallic surfaces on passing from the solid to the liquid state

Abstract

Some experiments described in a previous paper have shown that when a metal is made the cathode in a dilute acid electrolyte, the quantity of electricity passed across the interface, in order to cause a given change in the electrode potential, is determined by the accessible area of the metal surface, and is, to a first approximation, independent of the chemical nature of the surface. The accessible area in this case would correspond to the surface of the metal which is wetted by the electrolyte or which is accessible to hydrogen ions from solution, i. e. , it is the area of the metal-electrolyte interface. By a measurement of this quantity of electricity ∆Q it is possible to compare the accessible areas of different metallic surfaces. That the quantity ∆Q depends on the physical state of the metal surface and is independent of its chemical nature was shown by a comparison of ∆Q for mercury, for liquid amalgams and for platinised mercury. For the sake of completeness it seemed advisable to verify this for metals of quite different chemical composition, and experiments have been made on a fusible alloy and on molten gallium.