Next, we performed ECH experiments to validate the trends predicted by theoretical studies. For this, AP was chosen as a model substrate because: (i) the C=O group is activated by the aromatic structure; and (ii) the hydrogenation of AP is the most common route of producing 1-PEA (Fig. ), an important precursor in pharmaceutical and fragrance industries.(37) Among the metal cathodes investigated in this work, Cu was first studied to drive the ECH of AP, as it was predicted to be one of the most active ones by DFT calculations. The Cu electrocatalyst was prepared by an electrodeposition method following a previously reported protocol (see Supplementary Materials). Scanning electron microscopy (SEM) analysis showed a porous dendritic morphology (Supplementary Figure ) of the Cu catalyst, whereas X-ray diffraction (XRD) analysis showed the crystal planes of the Cu catalyst (Supplementary Figure ). Electrochemistry experiments were performed in aqueous potassium phosphate buffer solution (pH = 11.8). Details of the experimental setup can be found in the Supplementary Materials. Cyclic voltammograms (CVs) collected on the Cu electrocatalyst (Supplementary Figure ) revealed a significant increase in current density upon the addition of AP into the electrolyte solution, indicating the ability of Cu to promote ECH. Chronoamperometry experiments were then conducted within a potential window of -0.28 and -0.68 VRHE, and the reaction mixture was analyzed by proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy after 1 h to quantify the yield of 1-PEA. The FE and partial current density towards 1-PEA (FE1-PEA and J1-PEA, respectively) are shown in Fig. . A FE1-PEA of 41±6% and J1-PEA of 1.9±0.4 mA cm -2 were observed at -0.28 VRHE, which increased with more reducing potentials, reaching maximum values of 91±3% and 14±1 mA cm -2 , respectively, at -0.48 VRHE. The remaining product was confirmed to be H2 by gas chromatography. The FE1-PEA and J1-PEA started to decrease at higher potentials, between -0.58 and -0.68 VRHE. Optimization of the electrolyte pH and Cu catalyst deposition time is shown in Supplementary Figure , which reveals an optimal pH of 11.8 and a deposition time of 40 s.