A Flexible Electrochemical Sensor Based on Fe/Ce Dual Single-Atom Nanozyme for Detection of Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) is an indispensable mediator in cellular signaling pathways, playing a multifaceted role in biological systems. The development of advanced catalysts derived from flexible sensors for the real-time monitoring of dynamic H₂O₂ in vivo remains an important research issue. Recently, dual single-atom catalyst-based nanozymes exhibit synergistically enhanced catalytic performance, displaying excellent potential for H₂O₂ detection. Nevertheless, rationally regulating the geometric structures and electron transfer between the two metals still pose significant challenges. Hence, in this study, an advanced Fe/Ce dual single-atom catalyst (Fe/Ce-C)-based nanozyme was constructed, which proposes a Ce single-atom doping strategy to alter the electronic structure of Fe single-atom sites, endowing it with a high adsorption energy for hydroxyl groups to reduce the energy barrier of H₂O₂ in the reaction. This Fe/Ce-C achieves a linear sensing behavior in the range of 0.5-10,000 μM with a response speed of 1.4 s, a detection limit of 0.223 μM, and a sensitivity of 213 μA/mM·cm². Furthermore, the nanozyme-derived flexible electrochemical sensor was assembled for real-time monitoring of H₂O₂ concentration changes in the brains of living rats, exhibiting long-term detection capability and excellent in vivo biocompatibility. Such an Fe/Ce dual single-atom nanozyme-based electrochemical sensor can serve as a promising tool for monitoring diseases like Parkinson's.