Water electrolysis is a promising method for producing green hydrogen using renewable electricity, but the reliance on high-purity water feeds poses challenges with freshwater scarcity on large scales. This article explores the potential of direct seawater splitting as a solution, highlighting the issues of pH fluctuations, salt deposition, and competitive reactions in natural seawater electrolysis. Researchers have developed a membrane-based seawater electrolyser with high ion-blocking efficiency, but it requires a relatively high voltage for operation. To address challenges like salt deposition and sluggish kinetics in seawater electrolysis, a molybdenum nitride (Mo2N) catalyst was introduced. The catalyst showed improved performance by preventing hydroxide formation at the cathode and enhancing hydrogen transfer kinetics through NH4+ cations. The study prepared various transition metal nitrides (TMNs) using plasma-enhanced chemical vapor deposition (PECVD) and demonstrated the effectiveness of Mo2N in improving the efficiency and stability of seawater electrolysis. These findings mark a significant advancement in developing efficient and durable electrolysis devices for green hydrogen production from seawater, offering a potential solution to freshwater scarcity concerns.