Mechanistic insights on Bi-potentiodynamic control towards atomistic synthesis of electrocatalysts for hydrogen evolution reaction.

Herein, electrochemically assisted dissolution-deposition (EADD) is utilized over a three-electrode assembly to prepare an electrocatalyst for hydrogen evolution reaction (HER). Cyclic voltammetry is performed to yield atomistic loading of platinum (Pt) over SnS nanostructures via Pt dissolution from the counter electrode (CE). Astonishingly, the working electrode (WE) swept at 50 mV/s is found to compel Pt CE to experience 1000-3000 mV/s. The effect of different potential scan rates at the WE have provided insight into the change in Pt dissolution and its deposition behaviour over SnS in three electrode assembly. However, uncontrolled overpotentials at CE in a three-electrode assembly made Pt dissolution-deposition behavior complex. Here, for the first time, we have demonstrated bi-potentiodynamic control for dissolution deposition of Pt in four-electrode assembly over Nickel (Ni) foam. The dual cyclic voltammetry is applied to achieve better control and efficiency of the EADD process, engendering it as a pragmatically versatile and scalable synthesis technique.