Boosting Photo‐Electro‐Fenton Process Via Atomically Dispersed Iron Sites on Graphdiyne for InVitro Hydrogen Peroxide Detection

Hydrogen peroxide (H₂ O₂ ) is essential in oxidative stress and signal regulation of organs of animal body. Realizing in vitro quantification of H₂ O₂ released from organs is significant, but faces challenges due to short lifetime of H₂ O₂ and complex bio-environment. Herein, rationally designed and constructed a photoelectrochemical (PEC) sensor for in vitro sensing of H₂ O₂ , in which atomically dispersed iron active sites (Hemin) modified graphdiyne (Fe-GDY) serves as photoelectrode and catalyzes photo-electro-Fenton process. Sensitivity of Fe-GDY electrode is enhanced 8 times under illumination compared with dark condition. The PEC H₂ O₂ sensor under illumination delivers a wide linear range from 0.1 to 48 160 µm and a low detection limit of 33 nm, while demonstrating excellent selectivity and stability. The high performance of Fe-GDY is attributed to, first, energy levels matching of GDY and Hemin that effectively promotes the injection of photo-generated electrons from GDY to Fe³⁺ for reduced Fe²⁺ , which facilitates the Fe³⁺ /Fe²⁺ cycle. Second, the Fe²⁺ actively catalyzes H₂ O₂ to OH^- through the Fenton process, thereby improving the sensitivity. The PEC sensor demonstrates in vitro quantification of H₂ O₂ released from different organs, providing a promising approach for molecular sensing and disease diagnosis in organ levels.