The development of high-performance and cost-effective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts is highly required for electrochemical water splitting. The sluggish reaction kinetics, poor stability, and complicated processing restrict the practical application of most electrocatalysts. Herein, we report a facile oxygen corrosion strategy for the fabrication of Pt nanoparticles loaded on cobalt-iron layer double hydroxide (Pt-Co/Fe LDH) on iron foam using an oxygen corrosion method regulated by sodium chloride (NaCl). The as-prepared Pt-Co/Fe LDH electrodes feature overpotentials as low as 126 and 285 mV to deliver 100 mA cm–2 for HER and OER, respectively. Moreover, the Pt-Co/Fe LDH was applied as anode and cathode in an electrochemical electrolyzer and recorded a current density of 50 mA cm–2 at a small voltage of 1.66 V, which is superior to that of the Pt/C-FF || RuO2-FF system (1.89 V) and those of most previously reported electrocatalysts. The excellent electrocatalytic activity of Pt-Co/Fe LDH could be assigned to its specific structure, consisting of three-dimensional (3D) nanoflower-shaped nanosheets, favorable for promoting fast mass transport and ion diffusion and generating more active sites for the OER process. In addition, the synergistic effect between Pt and the Co/Fe LDH heterojunction structure effectively improves the electronic conductivity and H adsorption for HER performance. The oxygen corrosion method regulated by NaCl and interface engineering of the LDH structure is simple to implement and can be easily extended for the preparation of a plethora of other bifunctional and cost-effective electrocatalysts for various electrochemical processes.