An Electrochemical Cell Configuration Incorporating an Ion Conducting Membrane Separator between Reference and Working Electrode

Ionic impurities can significantly interfere with certain electrochemical measurements and should therefore be completely avoided. However, standard reference electrodes such as the widely used Saturated Calomel Electrode (SCE) and the Ag/AgCl electrode contain saturated chloride solutions. Typically, this chloride solution is only separated from the electrochemical cell electrolyte by a porous glass frit, which still allows chlorides to diffuse through and contaminate the electrochemical system. In order to avoid this undesired effect, a new electrochemical cell setup is presented here. The modification incorporates an ion conducting membrane that serves to further separate chloride containing reference electrodes from the electrochemical cell, and thereby actively prevents the diffusion of chlorides to the surface of the working electrode. The benefits of this modification, in particular for long-term electrochemical measurements in which the electrodes are positioned closely, is demonstrated by means of the investigation of the oxygen reduction reaction (ORR) on polycrystalline Pt in both a single- and three-compartment electrochemical cell.