A hierarchical rod-array structure Mo and Co-based oxidized/phosphide electroplated with FeOOH (NF@P-S450@FeOOH) composites on Ni foam (NF) was prepared via facile hydrothermal and electrodeposition methods. The as-synthesized rod-arrays exhibited excellent electrocatalytic performance and favorable stability for the oxygen evolution reaction (OER) under an alkaline atmosphere (overpotential of 240.5 mV under 100 mA cm⁻²). After doping P into Mo and Co-based oxidized (S450) nanorods, excellent composites were developed for the hydrogen evolution reaction (HER) with an overpotential of 162.8 mV under 100 mA cm⁻². Thus, an asymmetric setup composed of Mo and Co-based oxidized/phosphide (P-S450) nanorods and P-S450@FeOOH electrodes were constructed for overall seawater splitting, which delivered a potential of 1.828 V at 300 mA cm⁻² in alkaline simulated seawater (1 M KOH + 0.5 M NaCl). This work may provide a new method for overall seawater splitting using the reasonable design and synthesis of non-noble metal composites.