Synergistic CoCO₃/MnCO₃/TiO_x composite over nickel foam as anode for alkaline seawater electrolysis

The creation of chloride-resistant electrocatalysts for seawater electrolysis presents significant challenges due to the competing chlorine evolution reaction (CER), which results in considerable anodic corrosion. In this study, a CoCO₃/MnCO₃/TiO_x composite is developed on nickel foam (C₂M₁T_x/NF) using a solvothermal approach. Structural analyses confirm the presence of both CoCO₃ and MnCO₃ phases, which together form a microspherical structure that offers numerous accessible active sites and promotes favourable adsorption–desorption kinetics. The addition of TiO_x improves hydroxide adsorption and enhances structural stability. Electrochemical studies on alkaline seawater electrolysis (ASE) indicate that C₂M₁T_0.1/NF serves as an effective anode by facilitating the oxygen evolution reaction (OER) significantly below the onset potential for CER. The catalyst reaches a current density of 50 mA·cm−2 at an overpotential of 415 mV. Additionally, during overall water splitting at 1.92 V, the system exhibits stable performance for 100 h while sustaining a current density of 20 mA·cm−2. The improved performance is attributed to the synergistic Co–Mn redox coupling, structural and electronic modulation induced by Ti, and reduced chloro-oxidation due to CO₃2− species at the electrode–electrolyte interface, which enables selective and long-lasting ASE.