Efficient Hydrogen and Oxygen Evolution from Degenerate‐Doped Metallic WS ₂ Bifunctional Electrocatalyst

The changes in electronic and structural properties of transition metal dichalcogenide (TMDC)‐based electrocatalysts significantly affect the electrochemical water‐splitting activity. Herein, we report the efficient electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) bifunctional activity of Ru degenerate‐doped metallic WS 2 catalyst in alkaline electrolyte medium. WS 2 with a high percentage (14%) of Ru doping exhibits degenerate semiconductor nature with a structural phase transformation from the 2H‐hexagonal into the 1T‐octahedral phase. The 1T‐WS 2 degenerate semiconductor (WS 2 @Ru 14 ) catalyst demonstrates excellent bifunctional activity in 1 M KOH electrolyte with low overpotential ( η 10 = 112 mV vs. reversible hydrogen electrode [RHE] and 470 mV vs. RHE) and low Tafel slope ( b = 37 and 42 mV dec −1 ) for HER and OER activity, respectively. Further, the symmetric full‐cell electrolyzer constructed with a WS 2 @Ru 14 catalyst used as an anode and cathode for overall water splitting requires a cell voltage of 1.68 V to deliver a 10 mA cm −2 current density. The WS 2 @Ru 14 catalyst with high carrier density and intrinsic conductivity activates the basal plane and promotes electrochemical activity with fast electron transfer kinetics in the degenerate‐doped metallic WS 2 semiconductor. The density functional theory calculations throw light on understanding the phase stability and electronic band structure of the heavily doped WS 2 semiconductor. This work opens an avenue for rational design of doped TMDC electrocatalysts for clean energy generation.