The conversion of sunlight into chemical energy to produce solar hydrogen opens the door to one promising solution towards a sustainable alternative in the current energy crisis. Herein, we describe the successful synthesis of the first COF based on BOPHY dye (IEC-2) ever reported in the literature. Its β-ketoenamine linkage confers outstanding chemical stability for light-driven applications. The hybrid photocatalyst based on IEC-2 and TiO2 (10 wt% of COF loading) was studied for solar hydrogen evolution at both the lab-scale, and semi-pilot plant scale under natural sunlight. IEC-2@T-10 achieved a hydrogen production of 180.9 μmol g−1 under 6 h solar illumination, which increased by 36% with respect to that of benchmark TiO2. The high performance of IEC-2@T-10 results in a greater photonic efficiency than that of TiO2 (0.12% and 0.08%, respectively), highlighting the robustness of the BOPHY COF for light-mediated reactions.
