Amino-terminated polydimethylsiloxane modified porphyrin for efficiently biphasic photosynthesis of H 2 O 2

Abstract Hydrogen peroxide (H2O2) attracts widespread attention as a clean and sustainable oxidant. Nevertheless, porphyrin-based photocatalysts generally exhibit low H2O2 concentration in aqueous systems because the generated H2O2 does not accumulate effectively and is difficult to separate from the water. Here, we report an amino-terminated polydimethylsiloxane (NH2-PDMS) modified supramolecular tetrakis(4-carboxyphenyl) porphyrin (SA-TCPP) for effectively photocatalytic H2O2 production in a water/n-decane biphasic system. We illustrate that the formation of amide bonds (–CO–NH–) between NH2-PDMS and SA-TCPP regulates the catalyst’s surface from hydrophilic to hydrophobic, enabling its uniform dispersion in the nonpolar (n-decane) organic phase. We further demonstrate that this spatial distribution effectively separates the NH2-PDMS@SA-TCPP catalyst from the generated H2O2, allowing H2O2 to accumulate in the aqueous phase and reducing its decomposition. The NH2-PDMS@SA-TCPP catalyst delivers an H2O2 generation rate of 10.5 mM·h−1 and an apparent quantum efficiency as high as 16.02% at 420 nm. Additionally, in a long-term run, the accumulation of H2O2 with concentration is found to reach ca. 0.65 wt.%, close to the commercial level (1 wt.%–3 wt.%). This biphasic design provides a simple approach for efficient, stable, and sustainable H2O2 production.