All the ex-situ electrochemical characterizations were performed using an electrochemical workstation (Metrohm Autolab 302) in a custom-designed two-chamber three-electrode setup, with one half-cell having a glassy carbon disc (Area= 0.0314 cm 2 ) as working electrode, Ag/AgCl, sat. KCl -as a reference electrode (E 0 = 0.197 V vs RHE). The other half cell contains Pt-mesh as a counter electrode. The two half-cells were connected through a proton exchange membrane (Nafion 111). About 2.0 mg of catalyst was dispersed in 150 μL isopropyl alcohol and 10 μL 5% Nafion (as a binder), and then about 10 μL of this prepared ink was drop-casted on the glassy carbon (GC) disc. The electrochemical investigation was carried out in an aqueous 0.1 M KCl solution. All the potentials are reported against the reversible hydrogen electrode (RHE) using Eqn. 7.