AbstractThe development of high‐performance, low‐cost and rapid‐production bifunctional electrocatalysts towards overall water splitting still poses huge challenges. Herein, the authors utilize a facile hydrothermal method to synthesize a novel structure of Co‐doped ammonium lanthanum molybdate on Ni foams (Co‐ALMO@NF) as self‐supported electrocatalysts. Owing to large active surfaces, lattice defect and conductive channel for rapid charge transport, Co‐ALMO@NF exhibits good electrocatalytic performances which requires only 349/341 mV to achieve a high current density of 600 mA cm−2for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Besides, a low cell voltage of 1.52 V is required to reach the current density of 10 mA cm−2in alkaline medium along with an excellent long‐term stability for two‐electrode configurations. Density functional theory calculations are performed to reveal the reaction mechanism on Co‐ALMO@NF, which shows that the Mo site is the most favorable ones for HER, while the introduction of Co is beneficial to reduce the adsorption intensity on the surface of Co‐ALMO@NF, thus accelerating OER process. This work highlighted the importance of the structural design for self‐supporting electrocatalysts.