Quartz wool-supported porphyrin supramolecular photocatalysts for robust and scalable H2O2 generation

Abstract

Achieving stable immobilization of organic photocatalysts is essential for practical photocatalytic hydrogen peroxide (H₂O₂) production. In this study, we propose a robust photocatalytic strategy that immobilizes self-assembled porphyrin nanosheets (SA-TCPP) onto quartz wool (QW), using polydimethylsiloxane (PDMS) as both a binding and encapsulating medium. By optimizing the viscosity and operating temperature of PDMS, the resulting PDMS/SA-TCPP/QW composite achieves a high H₂O₂ yield of 95 μmol and maintains excellent stability over 10 cycles. The composite reaches a concentration of 7.4 mM and an internal quantum efficiency as high as 15.84% at 420 nm, which is comparable to that of SA-TCPP powder. In a modular flow reactor, it produced 3.5 mmol of H₂O₂ over 50 h, with the final solution concentrated to 100 mM, demonstrating strong scalability. In the PDMS/SA-TCPP/QW composite, PDMS forms a semi-solid interfacial layer that not only physically anchors the SA-TCPP nanosheets but also enhances interfacial stability through the formation of covalent amide (–CONH–) bonds. This integrated design offers a practical and broadly applicable strategy for the stable immobilization of organic photocatalysts.