Recent Progress in Design Strategy of Anode for Seawater Electrolysis

Abstract

Direct electrolysis of inexhaustible seawater to generate green hydrogen represents a more environment‐friendly technology relative to freshwater electrolysis. However, current seawater splitting suffers from a low catalytic efficiency and poor operation stability caused by anodic competition between the oxygen evolution reaction and the chlorine oxidation reaction as well as the severe chloride corrosion. This article provides a comprehensive overview of the latest achievements in promoting the selectivity and stability in seawater electrolysis. Beginning with the fundamentals of the anode reactions during seawater splitting, various strategies to design advanced anodic electrocatalyst including surface selective layer engineering, structural regulation by heteroatoms doping and vacancies, and heterostructure construction are discussed in detail. Finally, the conclusion and the challenges in developing seawater electrolysis technology are highlighted.

Tungstate Intercalated NiFe Layered Double Hydroxide Enables Long‐Term Alkaline Seawater Oxidation

“…[ 19 ] Therefore, the design of highly active and Cl − ‐resistant OER catalysts is crucial to promote the application of large‐scale seawater electrolysis. [ 20–25 ]…”

Insight into the Anticorrosion Behaviors of Phase-Transformed Cobalt Hydroxides for Long-Term Electrocatalytic Water Oxidation in Saline Electrolytes

“…Various anticorrosion strategies have been provided to extend the lifespan of anode electrodes. ,− One approach involves the direct addition of anionic additives, such as sulfate and phosphate, into the electrolyte. This addition facilitates the construction of negatively charged anion layers on the surface of the anode materials as these anions are preferentially adsorbed over Cl – .…”

Carbon Oxyanion Self‐Transformation on NiFe Oxalates Enables Long‐Term Ampere‐Level Current Density Seawater Oxidation

“…[16][17][18][19][20][21][22][23] At a given industrial-level j (e.g., 500 mA cm À 2 ), the electro-oxidation of Cl À still occurs freely on many catalysts, such as NiFe layered double hydroxide (LDH), [10] and competes with the OER to aggravate electrode dissolution. Even if the catalyst maintains high activity to avoid Cl À oxidation, Cl À itself can etch electrondeficient transition metals, [24] resulting in loss of reaction sites. So, the exploration of catalysts that sustain high OER activity at industrial-level j and suppress chlorine-related reactions well is the real core to overcome issues of inferior seawater oxidation performance, especially the limited electrode lifespan, caused by damaging chlorine chemistry.…”