Bimetallic transition metal dichalcogenides NixMo1-xSSe as efficient electrocatalysts for hydrogen evolution reaction in protic electrolyte

The electrochemical hydrogen evolution reaction (HER) is an efficient pathway to meet the energy crisis around the world. Two-dimensional transition metal dichalcogenides are potential electrocatalysts for hydrogen production. Designing efficient and inexpensive electrocatalysts for HER is crucial to large-scale industrialization. Herein, we have designed a bimetallic electrocatalyst with Ni and Mo as metals and introduced both S and Se as chalcogenides. The bimetallic electrocatalyst Ni0.25Mo0.75SSe exhibited excellent HER performance, requiring only an overpotential of 214 mV versus RHE to achieve a current density of 10 mA/cm2. The electrocatalysts Ni0.5Mo0.5SSe and Ni0.75Mo0.25SSe also exhibited an overpotential of 466 mV and 364 mV, respectively, compared to MoSSe of 602 mV at 10 mA/cm2. The improved activity is ascribed to the incorporation of a Ni transition metal atom, which provides the path for effective charge transfer during the electrolysis resulting in a reduction of Gibbs free energy associated with hydrogen adsorption. The EIS reveals lower charge transfer resistance (Rct) for Ni0.25Mo0.75SSe and also exhibits high stability. © 2025 Elsevier Ltd