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

Abstract Hydrogen peroxide (H 2 O 2 ) is essential in oxidative stress and signal regulation of organs of animal body. Realizing in vitro quantification of H 2 O 2 released from organs is significant, but faces challenges due to short lifetime of H 2 O 2 and complex bio‐environment. Herein, rationally designed and constructed a photoelectrochemical (PEC) sensor for in vitro sensing of H 2 O 2 , 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 H 2 O 2 sensor under illumination delivers a wide linear range from 0.1 to 48 160 µ m and a low detection limit of 33 n m , 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 Fe 3+ for reduced Fe 2+ , which facilitates the Fe 3+ /Fe 2+ cycle. Second, the Fe 2+ actively catalyzes H 2 O 2 to OH ‐ through the Fenton process, thereby improving the sensitivity. The PEC sensor demonstrates in vitro quantification of H 2 O 2 released from different organs, providing a promising approach for molecular sensing and disease diagnosis in organ levels.