Green Hydrogen Production by Alkaline Seawater Electrolyzers: A Journey from Lab-Scale Research to Industrial Applications

Abstract

Seawater offers an abundant and sustainable alternative to freshwater-based electrolysis, making it a key driver in addressing global water scarcity while advancing the hydrogen economy. However, the commercialization of seawater electrolysis faces several challenges, including catalyst degradation, membrane fouling, and competing chloride oxidation, which hinder long-term operational stability. This review provides a comprehensive analysis of the fundamentals, advantages, and challenges associated with seawater electrolysis, along with a snippet of advanced catalysts, new membrane technologies, and unique system designs. Selfsupporting electrode architectures, surface protection tactics, and innovative electrolyzer designs are discussed to enhance durability and ensure sustained operation under industrially relevant conditions. Additionally, this review highlights emerging approaches, including in situ purification systems, forward osmosis membranes, and hybrid seawater electrolyzers, which hold significant potential for reducing operational costs and improving overall system efficiency. From a techno-economic perspective, this work evaluates the capital expenditure (CapEx) and operating expenses (OpEx) associated with seawater electrolyzers, offering insights into the levelized cost of hydrogen (LCOH) and the economic feasibility. Lastly, it presents a roadmap for future research and industrialization, identifying key areas where innovation is needed to accelerate the development of commercially viable seawater electrolyzers.