Ketyl radical-mediated exfoliation and electron storage for solar hydrogen peroxide production

Efficient photocatalytic production of hydrogen peroxide is a sustainable strategy for green chemical synthesis and environmental remediation. Herein, we report TPM-DADK, a segmented π-conjugation polymer containing redox-active anthrazolines and tetraphenylmethane nodes, enabling visible-light-driven hydrogen peroxide generation through a direct two-electron oxygen reduction reaction pathway. Conjugation breaks promote electron localization and the formation of long-lived ketyl radical anions, which act as both electron reservoirs and triggers light-induced exfoliation into nanosheets with abundant active sites. This structural evolution, together with localized negative charges, enhances oxygen adsorption and activation through proton-coupled electron transfer. Spectroscopic and kinetic analyses reveal more efficient charge separation, longer excited-state lifetimes, and reduced recombination after exfoliation. In this work, we show that TPM-DADK achieves a hydrogen peroxide production rate of 17.22 mmol g^-1 h^-1 under simulated sunlight with a solar-to-chemical conversion efficiency of 3.07%, demonstrating that precise π-topology control and radical stabilization synergistically enhance solar-to-chemical conversion for sustainable photosynthesis.