# Industrial‐Scale Seawater Splitting at Engineered Interface of Boron‐Doped Cobalt Sulfide/Metal–Organic Framework Nanosheets Heterostructure

## TL;DR

A new catalyst for seawater splitting is developed to improve efficiency and durability by using boron-doped cobalt sulfide and metal-organic framework nanosheets.

## Contribution

The novel B-CoS2/MOF heterostructure enables chlorine-resistant seawater electrolysis with high efficiency and stability.

## Key findings

- The B-CoS2/MOF catalyst achieves 1.0 A cm−2 current density at 542 mV overpotential in alkaline seawater.
- The catalyst operates stably for 600 hours, resisting chlorine-induced degradation.
- Strong interfacial coupling and sulfate-mediated chloride repulsion are key to the catalyst's performance.

## Abstract

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.

Boron‐doped cobalt sulfide protected by the metal‐organic framework sheets (B‐CoS2/MOF heterostructures) enable selective oxygen evolution reaction in alkaline seawater via enhanced interfacial coupling, optimized hydroxide (OH‐) adsorption, and sulfate (SO4
2
−)‐mediated chloride (Cl−) repulsion, achieving 1 A cm−
2 at 542 mV with 600 h stability.© 2026 WILEY‐VCH GmbH