Vanadium Carbide Film Formed through Molten Salt Electrolysis of Sodium Metavanadate for Efficient Electrocatalytic Hydrogen Evolution

The utilization of non-precious electrocatalysts is key-enabling to mitigate challenges in energy and environmental sustainability. Herein, we report a vanadium carbide (VC) film generated from molten salt electrolysis of sodium metavanadate (NaVO3) on carbon cloth cathode. The VC forms on carbon cloth by spontaneous thermal nucleation and electrochemical growth. The molten salt electrolysis enhances the adhesion and electronic interaction of VC films with carbon cloth, resulting in an electrocatalytic activity for hydrogen evolution with a low overpotential (97 mV) at 10 mA cm−2 and long-lasting stability (50 h) in acidic media. This work provides a molten salt electrolysis integrating preparation of electrocatalysts and value-added utilization of vanadium slag.