A scalable approach using a gC3N4-covalent organic framework hybrid catalyst towards sustainable hydrogen production from seawater and wastewater

The photocatalytic generation of H₂ using covalent organic frameworks (COFs) is gaining more interest. While numerous reports have focused on the production of H₂ from deionized water using COFs, the inability to produce H₂ from industrial wastewater or seawater is a common limitation in many reported catalysts. Additionally, many of these reports lack a clear path to scale up the catalyst synthesis. In this study, we explore the prospect of hybridizing a COF with gC3N4 to create a robust photocatalyst for efficient H₂ generation. This hybrid exhibits outstanding performance not only in deionized water, but also in wastewater, and simulated seawater. Furthermore, we explore the feasibility of the bulk-scale synthesis and successfully produce a 20 g hybrid catalyst in a single batch, and the synthesis method is scalable to achieve the commercial target. Remarkably, a maximum HER rate of 94 873 μmol g⁻¹ h⁻¹ and 109 125 μmol g⁻¹ h⁻¹ was obtained for the hybrid catalyst from industrial wastewater and simulated seawater, respectively. The performance of bulk-scale batches closely matches that of the small-scale ones. This research paves the way for the utilization of organic photocatalysts on a commercial scale, offering a promising solution for sustainable large-scale H₂ production.