Hydrogen Oxidation beyond Water: In Search of Proton Mediation Pathways

Non-aqueous electrolytes offer cathodic selectivity advantages and are often paired with the hydrogen oxidation reaction. We investigate the effects of different solvents, along with the addition of water and ethanol, using cyclic voltammetry with polycrystalline platinum. To enable comparison with aqueous systems, ferrocene is used to calibrate the reference potential against the Standard Hydrogen Electrode (SHE), resulting in a measured potential of EFc+/Fc = 0.42 VSHE. In addition, we investigate the proton pumping abilities of a non-aqueous system by means of a flow-cell setup combined with real-time mass spectrometry. The results demonstrate a strong dependence of HOR activity on the electrolyte medium, highlighting the significant role of solvent and additive selection in non-aqueous electrochemical systems.