Triazine Engineering in Conjugated Microporous Polymers for Hydrogen Peroxide Photosynthesis

The photocatalytic synthesis of hydrogen peroxide (H₂O₂) via synergistic water oxidation (WOR) and oxygen reduction (ORR) dual-channel pathways presents a promising strategy to address global energy and environmental challenges. Herein, two kinds of porous conjugated microporous polymers (CMPs) functionalized with triazinyl and phenyl elements (denoted as TCMPs and PCMPs) are synthesized using a facile one-pot polycondensation strategy. The incorporation of electron-deficient triazine rings (Tz) into the highly conjugated CMPs framework substantially enhances photocatalytic performance. Under natural sunlight using only water and air as reactants, TCMP-1 achieves an exceptional H₂O₂ generation rate of 783.9 µm h⁻¹, representing a 6-fold enhancement over PCMP-1 (130.9 µm h⁻¹). Comparative analyses demonstrate that Tz in the donor-acceptor (D-A) system promotes the delocalization of photoexcited charges, promoting efficient electron donation to O₂ and thus offering a favorable ORR for H₂O₂. Furthermore, the electron-deficient nature of the Tz facilitates ORR to form superoxide radicals (·O₂⁻), which are key intermediates in H₂O₂ formation. In situ characterizations combined with theoretical calculations verified the concurrent involvement of ORR and WOR pathways in the H₂O₂ production process. The findings establish triazine engineering as a universal paradigm for designing high-performance CMP photocatalysts, offering significant avenues for sustainable energy conversion and environmental remediation.