Functionalized Modification of Conjugated Porous Polymers for Full Reaction Photosynthesis of H2O2

Modulating the molecular structure to achieve the full reaction including oxygen reduction reaction and water oxidation reaction is a promising strategy for efficient photosynthesis of hydrogen peroxide (H₂O₂) but remains a challenge. Herein, a triphenylamine and naphthalimide-based conjugated porous polymers are synthesized with photo oxidation-reduction structures, then sulfonate (─SO₃H) and quaternary ammonium groups are introduced via a post-modification strategy to produce two photocatalysts named NI-TPA-NI-SO₃H and NI-TPA-NI-N, respectively. Introducing charged functional groups has improved the hydrophilicity and oxygen (O₂) adsorption, beyond that, the ─SO₃H further stabilizes the adsorbed O₂ via hydrogen bonding as well as accelerates the photogenerated carrier separation and electron/proton transport that enables full reaction photosynthesis of H₂O₂. Therefore, motivated by efficient charge separation, stabilized O₂ adsorption, and boosted proton-coupled electron transfer, NI-TPA-NI-SO₃H exhibits the highest light-driven H₂O₂ production rate among the three photocatalysts, reaching 3.40 mmol g⁻¹ h⁻¹, which is 4.9-fold of NI-TPA-NI. Remarkably, in the presence of ethylenediaminetetraacetic acid disodium salt, its rate significantly enhances to 14.5 mmol g⁻¹ h⁻¹, superior to most reported organic photocatalysts to the best of the knowledge.