Efficient bifunctional vanadium-doped Ni3S2 nanorod array for overall water splitting

Abstract

Electrochemical water splitting, allowing energy conversion from renewable resources into non-polluting chemical fuels, is vital for future sustainable energy systems, and great efforts have been made for developing efficient and cheap bifunctional electrocatalysts. Herein we report a bifunctional vanadium-doped Ni₃S₂ nanorod array electrode for overall water splitting in alkaline media. To afford a catalytic current of 10 mA cm⁻², the designed V-Ni₃S₂ electrode only requires overpotentials of 133 mV for hydrogen evolution and 148 mV for oxygen generation, meanwhile showing high long-term stability. The excellent catalytic properties are attributed to the V dopant and geometric advantages of the nanorod array. The V-Ni₃S₂ electrodes are simultaneously utilized as cathode and anode in one two-electrode cell for overall water splitting, exhibiting a cell voltage of 1.421 V at 10 mA cm⁻². The water splitting in this cell can also be feasibly driven by a single-cell AA battery (1.5 V). Our report shows substantial advancement in the exploration of efficient bifunctional electrocatalysts for water splitting.