Yifan Xu

The achievement of conductive bifunctional covalent organic frameworks (COFs) for overall water splitting remains challenging due to the lack of multifunctional active sites. Herein, the atomically dispersed electroactive iridium‐ruthenium dual‐active sites are anchored on donor‐acceptor‐based redox‐active COF (Ace and TAPT, IrRu DAS/AT‐COF) as a pyrolysis‐free electrocatalyst for alkaline water electrolysis application. The as‐synthesized IrRu DAS/AT‐COF exhibits robust bifunctional activities and stability for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, surpassing the benchmarks and most recent noble‐metal‐based catalysts. Operando spectroscopy and theoretical calculations unveil the multiple active sites separation mechanism on IrRu DAS/AT‐COF, where the giant multifunctional active‐site synergistic enhancement (MASE) effect was triggered by the intramolecular compensating electronic modulations between the Ir _SA and Ru _SA sites. This setting can balance the competitive effects of the following elementary steps and simultaneously accelerate them into the local environment of catalytic units, including (i) the improved conductivity and H ₂ O adsorption, (ii) decreased H ₂ O dissociation energy barrier, (iii) optimal adsorption of H/O intermediates. This work provides new insights into the design of multi‐site catalytic local environments in bifunctional COFs electrocatalysts for water electrolysis.

Direct seawater electrolysis (DSE) is a promising technology for sustainable hydrogen production, utilizing abundant marine resources. However, industrialization of DSE faces significant long-term stability challenges due to the complex composition of seawater, which contains various ions and microorganisms that can lead to both chemical and physical degradation of the electrolysis system. For instance, the presence of chloride ions (Cl⁻) hinders the desired oxygen evolution reaction (OER) because competing chlorine evolution reactions (CER) occur and adversely impact electrode materials, resulting in low system efficiency and poor longevity. To enhance long-term stability of DSE, researchers are investigating robust electrocatalysts and advanced surface modifications that improve protection against corrosive environments and enhance selectivity. Innovative electrode designs are also being developed to manage bubble transport and decrease precipitation. Additionally, the design of electrolysis cells, such as bipolar membrane cells, offers a viable solution by minimizing Cl⁻ transport and corrosive environment. With an increasing number of offshore renewable energy projects, the integration of effective DSE technologies in the offshore environment is critical. This review provides the state-of-the-art of electrodes, cells and systems, contributing to the development of DSE for long-term stable operation.