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

The photocatalytic generation of H using covalent organic frameworks (COFs) is gaining more interest. While numerous reports have focused on the production of H from deionized water using COFs, the inability to produce H 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 gCN to create a robust photocatalyst for efficient H 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 h and 109 125 μmol g h 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 H production.