Enhanced redox kinetics for hydrogen peroxide photosynthesis in high-concentration by encapsulating porphyrin metal–organic frameworks with phenolic resin

Abstract

Photocatalytic hydrogen peroxide (H2O2) production (PHP) represents a promising strategy for substituting the anthraquinone process, yet the sluggish redox kinetics causes strong oxidizing superoxide intermediate rapid accumulation, resulting in poor reaction performance and stability. Herein, we report an interface-adapted all-organic step-scheme (S-scheme) photocatalyst based on Hf-based porphyrin metal-organic frameworks (Hf-PMOFs) and benzoxazine-based 3-aminophenol-formaldehyde (APF) resin, realizing a record-high H2O2 yield of 2995.13 μmol h- g1 using porphyrin-based photocatalysts in pure water and a quantum efficiency of 4.53% under 420 nm. The concentration of the obtained H2O2 solution reaches 6.93 mM in the continuous test, meeting the potential for on-site photosynthesis. This achievement results from the encapsulation of APF to provide channels for charge transfer and modulate surface electronic structure to eliminate the reaction energy barrier of *OOH intermediate, accelerating the conversion of superoxide intermediate. We show that the PHP can be performed by utilizing domestic water sources, suggesting its wide applicability. Furthermore, we construct a floatable platform based on Hf-PMOF/APF to in situ supply H2O2 for Fenton reaction under light irradiation towards tetracycline hydrochloride degradation. This empirical evidence confirms that encapsulating porphyrin-based photocatalysts with resin can enhance charge dynamics and optimize redox capability of photocatalytic system towards advancing the development of practical photocatalytic applications.