摘要： Electrochemical water splitting, allowing energy conversion from renewable resources into non-polluting chemical fuels, is vital in the future sustainable energy system, and great efforts have been paid on 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 the overpotentials of 133 mV for hydrogen evolution and 148 mV for oxygen generation, meanwhile showing high long-term stability. The excellent catalytic properties are assigned to the V dopants and geometric advantages of nanorod array. The V-Ni3S2 electrodes are simultaneously utilized as cathode and anode in one two-electrode cell to function 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.