Effective H₂O₂ Photosynthesis in Gas–Liquid–Solid Triphase System with Self‐Floating Conjugated Organic Polymers

Abstract Solar‐driven photocatalytic oxygen reduction is a promising pathway for sustainable hydrogen peroxide (H₂O₂) production. However, limited O₂ diffusion and low selectivity in the two‐electron oxygen reduction reaction hinder its practical application. Here, a novel conjugated organic polymer material (conjugated triazine‐thiophene polymer, CTTP) based on triazine and thiophene, integrating a favorable mass transfer structure with competent catalytic centers is presented for the first time. Remarkably, under the gas–liquid–solid triphase condition, the self‐floating CTTP can rapidly capture gaseous oxygen, reducing it to superoxide radicals and transferring them to the reaction interface, drastically enhancing H₂O₂ yield. An excellent H₂O₂ concentration of 1.85 mm g⁻¹ h⁻¹ is achieved in a triphase system, representing a remarkable 14‐fold improvement compared to the liquid and solid phase reaction. Interestingly, the triphase system based on CTTP demonstrates the potential for large‐scale H₂O₂ production under 8 h of sunlight irradiation, reaching 293 ppm day⁻¹ m⁻². This work opens up a new avenue for the construction of sustainable H₂O₂ production systems and may stimulate future related research.