A Flexible Electrochemical Sensor Based on Porous Ceria Hollow Microspheres Nanozyme for Sensitive Detection of H₂O₂

The development of cost-effective and highly sensitive hydrogen peroxide (H₂O₂) biosensors with robust stability is critical due to the pivotal role of H₂O₂ in biological processes and its broad utility across various applications. In this work, porous ceria hollow microspheres (CeO₂-phm) were synthesized using a solvothermal synthesis method and employed in the construction of an electrochemical biosensor for H₂O₂ detection. The resulting CeO₂-phm featured a uniform pore size centered at 3.4 nm and a high specific surface area of 168.6 m²/g. These structural attributes contribute to an increased number of active catalytic sites and promote efficient electrolyte penetration and charge transport, thereby enhancing its electrochemical sensing performance. When integrated into screen-printed carbon electrodes (CeO₂-phm/cMWCNTs/SPCE), the CeO₂-phm/cMWCNTs/SPCE-based biosensor exhibited a wide linear detection range from 0.5 to 450 μM, a low detection limit of 0.017 μM, and a high sensitivity of 2070.9 and 2161.6 μA·mM^-1·cm^-2-surpassing the performance of many previously reported H₂O₂ sensors. In addition, the CeO₂-phm/cMWCNTs/SPCE-based biosensor possesses excellent anti-interference performance, repeatability, reproducibility, and stability. Its effectiveness was further validated through successful application in real sample analysis. Hence, CeO₂-phm with solvothermal synthesis has great potential applications as a sensing material for the quantitative determination of H₂O₂.