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

Abstract

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.