Industrial-Scale Seawater Splitting at Engineered Interface of Boron-Doped Cobalt Sulfide/Metal-Organic Framework...

Seawater electrolysis faces several significant obstacles, including low energy efficiency and anode corrosion due to chlorine chemistry, which limit its practical potential. To overcome this, we developed a catalyst composed of boron-doped CoS₂ protected by metal-organic framework sheets (MOFs) (B-CoS₂/MOF heterostructures). Introducing B atoms into the CoS₂ layer tunes the surface chemistry to promote adhesion of Ni-MOF. Density functional theory calculations indicate a strong interaction at the heterointerface, with a binding energy of -4.13 eV, where the MOF anchors onto the B-CoS₂ surface through a Ni-S bond measuring 2.08 Å, confirming the presence of an ionic bond. This strong heterointerface promotes OH^- adsorption while repelling Cl^- ions due to the presence of SO₄ ^2-, effectively mitigating chlorine-induced degradation. Therefore, the B-CoS₂/MOF catalyst achieves an industrial-scale current density of 1.0 A cm^-2 at an overpotential of 542 mV in alkaline seawater and operates stably for 600 h, hence suggesting the potential for designing cost-effective, chlorine-resistant systems for practical seawater splitting.