Electrochemical saline water electrolysis using renewable energy as input is a highly desirable and sustainable method for the mass production of green hydrogen^{1,2,3,4,5,6,7}; however, its practical viability is seriously challenged by insufficient durability because of the electrode side reactions and corrosion issues arising from the complex components of seawater. Although catalyst engineering using polyanion coatings to suppress corrosion by chloride ions or creating highly selective electrocatalysts has been extensively exploited with modest success, it is still far from satisfactory for practical applications^{8,9,10,11,12,13,14}. Indirect seawater splitting by using a pre-desalination process can avoid side-reaction and corrosion problems^{15,16,17,18,19,20,21}, but it requires additional energy input, making it economically less attractive. In addition, the independent bulky desalination system makes seawater electrolysis systems less flexible in terms of size. Here we propose a direct seawater electrolysis method for hydrogen production that radically addresses the side-reaction and corrosion problems. A demonstration system was stably operated at a current density of 250 milliamperes per square centimetre for over 3,200 hours under practical application conditions without failure. This strategy realizes efficient, size-flexible and scalable direct seawater electrolysis in a way similar to freshwater splitting without a notable increase in operation cost, and has high potential for practical application. Importantly, this configuration and mechanism promises further applications in simultaneous water-based effluent treatment and resource recovery and hydrogen generation in one step.

使用可再生能源作为输入的电化学盐水电解是大规模生产绿色氢^{1,2,3,4,5,6,7}的一种非常理想且可持续的方法；然而，由于海水的复杂成分引起的电极副反应和腐蚀问题，其实际可行性受到耐久性不足的严重挑战。尽管使用聚阴离子涂层抑制氯离子腐蚀或产生高选择性电催化剂的催化剂工程已得到广泛开发并取得了一定的成功，但在实际应用中仍远不能令人满意^{8,9,10,11,12,13,14}。使用预脱盐工艺间接分解海水可避免副反应和腐蚀问题^{15,16,17,18,19,20,21}，但它需要额外的能量输入，使其在经济上缺乏吸引力。此外，独立庞大的海水淡化系统使得海水电解系统在尺寸上的灵活性较差。在这里，我们提出了一种用于制氢的直接海水电解方法，该方法从根本上解决了副反应和腐蚀问题。演示系统在实际应用条件下，在250毫安/平方厘米的电流密度下稳定运行了3200多个小时，没有出现故障。该策略以类似于淡水分解的方式实现了高效、尺寸灵活和可扩展的直接海水电解，并且没有显着增加运营成本，具有很高的实际应用潜力。重要的，