Reversibility of the GeH/GeOH transformation at a Ge electrode: an EQCM study

We present a combined cyclic voltammetry and electrochemical quartz-crystal micro-balance study of a thin-layer germanium electrode in 1 M HClO4 electrolyte. When the potential is more positive than −0.2 V versus SCE, significant mass loss occurs due to anodic dissolution. However, when the potential is cycled in a range below −0.2 V versus SCE, only periodic variations of mass are observed, corresponding to the quasi-reversible change of the surface between a hydrogenated state and a hydroxylated state. These data provide the as yet missing clearcut proof that this change of state takes place without any dissolution of the electrode.