Characterization of porous Pt films deposited via sputtering

This paper investigates the effect of platinum catalyst thickness and morphology on the electrochemical surface area using electron microscopy and cyclic voltammetry. The roughness and porosity of platinum catalyst are varied by using different argon pressures during platinum sputter-deposition process. Lower argon pressure results in denser and smoother platinum films, which are confirmed by scanning electron microscopy and atomic force microscopy, respectively. The cyclic voltammetry is then used to quantify the catalytic activity of the films with various thickness and morphology. The electrochemical surface area extracted from the cyclic voltammetry shows that the current density is enhanced by 4-5 orders of magnitude through the formation of finite amount of porosity using a higher argon pressure (>60 mTorr) compared to a highly dense film.