Tailored covalent organic framework–based heterostructures for integrated electrochemical water splitting and reduction reactions: Interfacial design and charge transfer optimization

The development of sustainable and efficient strategies for water splitting and carbon dioxide (CO₂) reduction is critical for advancing clean energy technologies. Covalent Organic Frameworks (COFs), owing to their tunable porosity, high surface area, and structural modularity, have emerged as promising platforms for constructing hybrid photocatalysts and electrocatalysts. This review highlights recent progress in the integration of COFs into composite systems designed for overall water splitting oxygen and CO₂ reduction reactions (ORR, CO₂RR). By leveraging the inherent structural versatility of COFs, their catalytic activity toward the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), ORR and CO₂RR can be significantly enhanced. The incorporation of COFs with conductive components such as metal oxides, metal nanoparticles, and carbon-based materials enables synergistic interactions that improve charge transport, enhance catalytic stability, and facilitate reaction kinetics. We discuss various synthetic and post-synthetic modification strategies that enable precise control overactive site exposure and interfacial charge dynamics. Furthermore, we examine the structure–property–performance relationships in COF-based hybrids and their role in optimizing catalytic efficiency.