The electrochemical setup consisted on a divided H-cell (Supporting Information, Figure ), in which the cathodic and anodic compartments are separated by a silica frit. Unless otherwise stated, all experiments were carried out at a fixed potential and open to air. A commercial Ni foam (Goodfellow) was used as the working electrode (1 cm 2 , 95% porosity). Potentials were measured vs an Ag/AgCl reference electrode. Electrochemical reactions were carried out using a GAMRY Interface E1010 or a Biologic VSP-3e potentiostat. Faradaic Efficiency (FE) was determined as the fraction of current used in the hydrogenation of interest compared with the total current. Reactions using Pd/C were purged with nitrogen gas before the addition of H2 to avoid ignition.