This paper addresses the hydrogen evolution reaction (HER) occurring on platinum in an aqueous solution containing dissolved CO2 at several pressures. A new setup that uses a low inertia rotating disk electrode (RDE) adapted in an autoclave is proposed. This setup allows obtaining polarizations curves and electro-hydrodynamic (EHD) impedance, the latter for the first time in pressured conditions. New equations to adjust the Levich plots are proposed and briefly discussed. (C) 2017 The Electrochemical Society. All rights reserved.