Regulating the structure and composition is an important strategy to obtain high efficiency electrocatalyst. Herein, this paper proposes an innovative plasma-assisted approach to synthesize an efficient electrocatalyst with multiple active components (Co nanoparticles, oxygen vacancies, and CoFe layered double hydroxide nanosheets) covered on CoP nanowire array (denoted as PD-CoFe LDH@CoP, 'PD' is defined as plasma-driven approach) for alkaline water/seawater splitting. The hierarchical nanostructure can endow the catalyst with more substantial mass transfer and expose more active sites. In contrast, the multiple active components can accelerate the electrocatalytic kinetics, making the PD-CoFe LDH@CoP electrocatalyst exhibit excellent catalytic activity. As a result, when assembling a two-electrode system, the assembled cell only needs an ultralow voltage of 1.79 V to reach 100 mA/cm