The article presents a novel electrocatalyst for direct seawater oxidation, which achieves high performance and long-term stability. The catalyst, named MoO3@CoO/CC, is constructed by depositing an ultra-thin amorphous molybdenum oxide (MoO3) layer on a beaded-like cobalt oxide (CoO) array on a three-dimensional carbon cloth (CC) using atomic layer deposition (ALD) technology. This structure forms a cowpea-like morphology that enhances the catalyst's efficiency in seawater electrolysis. The MoO3 layer serves as a directional confinement layer, inhibiting phase segregation and improving the catalyst's stability. It also shields chloride ions (Cl⁻) from reaching the catalytic active interface, enabling selective oxidation of seawater. The catalyst demonstrates high selectivity (Faraday efficiency of 100%) and stability, maintaining performance for over 500 hours at 1 A/cm² with a voltage of 1.93 V. The hydrogen production rate is 419.4 mL/cm²/h, and the power consumption is 4.62 kWh/m³ H₂, which is lower than that of pure water electrolysis. The catalyst's performance is attributed to its unique structure, which optimizes the reaction mechanism and enhances the kinetics of the oxygen evolution reaction (OER). The MoO3 layer also prevents deep interface reconstruction, maintaining the catalyst's structure and activity. The study highlights the importance of controlled surface reconstruction in developing high-performance OER catalysts for seawater electrolysis. The results demonstrate the potential of this catalyst for large-scale hydrogen production from seawater.The article presents a novel electrocatalyst for direct seawater oxidation, which achieves high performance and long-term stability. The catalyst, named MoO3@CoO/CC, is constructed by depositing an ultra-thin amorphous molybdenum oxide (MoO3) layer on a beaded-like cobalt oxide (CoO) array on a three-dimensional carbon cloth (CC) using atomic layer deposition (ALD) technology. This structure forms a cowpea-like morphology that enhances the catalyst's efficiency in seawater electrolysis. The MoO3 layer serves as a directional confinement layer, inhibiting phase segregation and improving the catalyst's stability. It also shields chloride ions (Cl⁻) from reaching the catalytic active interface, enabling selective oxidation of seawater. The catalyst demonstrates high selectivity (Faraday efficiency of 100%) and stability, maintaining performance for over 500 hours at 1 A/cm² with a voltage of 1.93 V. The hydrogen production rate is 419.4 mL/cm²/h, and the power consumption is 4.62 kWh/m³ H₂, which is lower than that of pure water electrolysis. The catalyst's performance is attributed to its unique structure, which optimizes the reaction mechanism and enhances the kinetics of the oxygen evolution reaction (OER). The MoO3 layer also prevents deep interface reconstruction, maintaining the catalyst's structure and activity. The study highlights the importance of controlled surface reconstruction in developing high-performance OER catalysts for seawater electrolysis. The results demonstrate the potential of this catalyst for large-scale hydrogen production from seawater.