Pre-introduced carbon dots on anode prior to nickel-iron layered double hydroxide growth for stable seawater splitting

Electrocatalytic seawater splitting is a promising technology for sustainable hydrogen production, but its practical application is hindered by the sluggish oxygen evolution reaction (OER) kinetics and corrosion from the chloride ions (Cl − ). Here, a strategy of pre-modifying the anode with carbon dots (CDs) before growing nickel-iron layered double hydroxide (NiFe LDH) is reported to improve its activity and stability in seawater (B-CDs/NiFe LDH). The introduced CDs can efficiently activate high-valent Fe sites and electrostatically repel Cl − to protect the nickel foam substrate. Compared to post-modification of CDs, this strategy reduces CDs dosage by 80 %, while achieving comparable OER performance. The synthesized B-CDs/NiFe LDH exhibits an overpotential of 349 mV at 100 mA cm −2 under alkaline seawater conditions, with electrocatalytic stability over 150 h. This work not only presents a viable approach to the fabrication of noble metal-free anodes for stable seawater electrolysis, but also provides theoretical guidance for the subsequent design of such electrode materials.