Alkaline seawater as an electrolyte for hydrogen production: A feasibility and performance study

Hydrogen production via alkaline water electrolysis is a mature technology, yet high costs and freshwaterconsumption remain key limitations. Given the scarcity of freshwater, seawater emerges as a promising alternative,though its chloride content poses corrosion challenges to conventional electrodes like nickel. In thisstudy, Ni-Nb₂O₅ composite electrodes were synthesized and tested as cathodes in a commercial electrolyzer(HYDROEL-1) using different electrolyte compositions: (a) 30% w/v KOH, (b) 30% w/v KOH with 3.43% w/vNaCl, (c) 5.6% w/v KOH with 3.43% w/v NaCl, and (d) 3.43% w/v NaCl. The results show that, under typicaloperating current densities (0.3–0.5 A/cm²), electrolyzer performance remains stable in the presence of NaClwhen strongly alkaline conditions are maintained. These findings support the feasibility of using moderatelyalkalized seawater as a cost-effective and sustainable solution for hydrogen generation. The study also highlightsthe potential of Ni-Nb₂O₅ electrodes in bridging laboratory advances with real-world needs, especially for coastalor off-grid hydrogen production where freshwater is scarce.