A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer

Direct seawater electrolysis is promising for sustainable hydrogen production but suffers severe side reactions and corrosion. Here, the authors report a corrosion-resistant electrocatalyst with in situ-formed chloride-ion-repelling cation layer for efficient and long-lasting seawater oxidation. Direct seawater electrolysis is promising for sustainable hydrogen gas (H-2) production. However, the chloride ions in seawater lead to side reactions and corrosion, which result in a low efficiency and poor stability of the electrocatalyst and hinder the use of seawater electrolysis technology. Here we report a corrosion-resistant RuMoNi electrocatalyst, in which the in situ-formed molybdate ions on its surface repel chloride ions. The electrocatalyst works stably for over 3000 h at a high current density of 500 mA cm(-2) in alkaline seawater electrolytes. Using the RuMoNi catalyst in an anion exchange membrane electrolyzer, we report an energy conversion efficiency of 77.9% and a current density of 1000 mA cm(-2) at 1.72 V. The calculated price per gallon of gasoline equivalent (GGE) of the H-2 produced is $ 0.85, which is lower than the 2026 technical target of $ 2.0/GGE set by the United Stated Department of Energy, thus, suggesting practicability of the technology.

Automated summary

The authors developed a corrosion-resistant electrocatalyst with a chloride-ion-repelling cation layer for efficient and long-lasting seawater oxidation. It showed stable performance for over 3000 hours and achieved a high energy conversion efficiency, suggesting the practicality of this technology.