Ultra-Durable Solar-Driven Seawater Electrolysis for Sustainable Hydrogen Production

Abstract

Ions in seawater hinder direct sewage electrolysis due to the extreme corrosion of Cl⁻ to the anode and reaction of Mg²⁺ and Ca²⁺ on the cathode producing solid substances, which reduce the electrolytic efficiency. However, traditional desalination consuming fossil fuel with massive CO₂ emissions threatens human survival. Therefore, zero-carbon emission, ultra-durable, large-scale production of freshwater from seawater for water electrolysis is urgently needed. Herein, a multifunctional system for seawater is demonstrated electrolysis based on ultra-durable solar desalination outdoors. The solar evaporators reach an evaporation flux of 1.88 kg m⁻² h⁻¹ with a photothermal conversion efficiency of solar energy as high as 91.3% with excellent ultra-durable salt resistance even for saturated saltwater due to the Marangoni effects. Moreover, the condensation of pure water from solar desalination based on the evaporation system reaches 0.54 L m⁻² h⁻¹ outdoors, which is suitable for a 20 cm × 20 cm engineered electrode equipped with a Janus membrane powered by a solar panel to produce H₂ outdoors. The ultrafast unidirectional transport of H₂ bubbles enabled by Janus membranes can greatly improve the H₂ production efficiency at a rate approaching 85 mL h⁻¹ for continuous 24 h outdoors.