Highly efficient sustainable strategies toward carbon-neutral energy production

Abstract

Seawater electrolysis driven by renewable energy (such as wind, solar and tidal energy) offers a promising route to produce high energy density hydrogen (H₂), which is a potentially attractive technology in the framework of carbon-neutral energy production. In contrast to the limited freshwater resource, seawater is an abundant resource that is receiving growing attention for electrolysis as it significantly alleviates the demand for freshwater use. Nevertheless, seawater electrolysis has so far suffered from low selectivity and poor stability issues for oxygen evolution reaction (OER) due to chloride-induced competitive oxidation reactions and corrosion, which seriously affects the H₂ production efficiency by seawater electrolysis and hinders the practical application of this technology. Herein, this review comprehensively overviews the recent progress of OER in seawater electrolysis, with an emphasis on the current effective strategies for achieving high OER selectivity and stability by the rational design of electrocatalysts, electrolytes and electrolyzers. Specifically, we first classify the design strategies to improve OER selectivity in seawater electrolysis, including the alkaline design criterion, designing selective OER active sites, decorating the Cl⁻ blocking layer, constructing a 3D hierarchical structure and engineering surface wettability. Moreover, the stability of OER can be improved significantly through some effective strategies, such as establishing a surface protective layer, in situ generating anti-corrosion species, structural buffer engineering, adding additives into the electrolyte, and designing electrolyzers. Finally, the remaining challenges and future perspectives for further development of seawater electrolysis systems are also proposed.