Fe-modified CoCr layered double hydroxides for boosting the seawater oxygen evolution reaction

Abstract

The development of efficient and stable oxygen evolution reaction (OER) electrocatalysts for seawater electrolysis is vital to enable sustainable hydrogen production in coastal and arid regions without further burdening scarce freshwater resources. Here, we report the design of an iron-modified cobalt–chromium layered double hydroxide (Fe–CoCr LDH) derived from a cobalt-based metal–organic framework (Co MOF) for the OER in alkaline seawater media. The synthesis was carried out entirely at room temperature using a rapid, solution-based process. The resulting Fe–CoCr LDH catalyst demonstrates high OER activity, achieving low overpotentials of 250, 300, and 320 mV at current densities of 100, 500, and 1000 mA cm⁻², respectively. Furthermore, the catalyst exhibits very good long-term stability in both 1 M KOH and 6 M KOH natural seawater, maintaining performance over 100 hours at 100 and 500 mA cm⁻². These results highlight the potential of earth-abundant transition metal-based LDHs as efficient OER electrocatalysts for seawater electrolysis applications.