Edge-Functionalized Metal-Free Polyphthalocyanine Networks for Efficient Photocatalytic H2O2 Production.

Hydrogen peroxide (H2O2) is a green oxidant with wide applications, but its industrial production via the anthraquinone process is energy-intensive and environmentally harmful. Photocatalytic H2O2 generation from water and oxygen under visible light offers a sustainable alternative, although current systems suffer from poor light absorption and fast charge recombination. Here, we report a molecular engineering strategy to enhance the photocatalytic H2O2 generation of phthalocyanine-based covalent polymers (PPc) by introducing naphthyl groups at the polymer edge. The resulting PPc-n shows a 2.77-fold improvement in the H2O2 production rate (174.15 μmol·g-1·h-1) compared to unmodified PPc-p under visible light with ethanol as a sacrificial agent. Mechanism studies, including EPR spectroscopy and reactive species trapping, reveal that PPc-n follows a two-step, single-electron oxygen reduction pathway, with •O2- as the key intermediate. This work highlights edge functionalization as an effective approach to enhancing light harvesting and charge separation in organic photocatalysts for green chemical synthesis.