Dynamic chloride ion repulsion facilitated by graphene quantum dots for stable electrolytic seawater oxidation

Hydrogen production via seawater electrolysis, leveraging sustainable energy sources such as offshore wind or solar energy, has immense application potential. However, the abundance of chloride ions (Cl − ) in seawater leads to the generation of chlorine gas and hypochlorite at the anode during electrolysis, posing a severe threat of corrosion of the catalyst and electrolytic equipment. Herein, we synthesize a NiMo-based catalyst adorned with surface-anchored graphene quantum dots (GQDs). This catalyst possesses excellent Cl − exclusion capabilities. The Mo–NiS/Se@GQDs core–shell nanorod catalyst requires only 170 mV of overpotential to attain a current density of 10 mA cm −2 and operates stably for 200 h without degradation across a broad current density range from 100 to 400 mA cm −2 . This remarkable electrocatalytic stability arises from the dynamic and efficient repulsion of Cl − at the catalytic interface, as proven by the post-reaction analysis of Cl − distribution within the catalyst. Furthermore, a potentiodynamic polarization test revealed that the Mo–NiS/Se@GQDs catalyst has high corrosion potential (0.66 V) and low corrosion current density (122.93 μA cm −2 ), underscoring its excellent corrosion resistance. This research presents a novel approach to mitigate Cl − corrosion during hydrogen production through seawater electrolysis, laying a solid foundation for advancing sustainable energy conversion technologies.