Hydrothermally Synthesized Metal Oxide Nanostructures for H2O2 Sensing and Oxidative Stress Management in Plants

Hydrogen peroxide (H2O2) is a key reactive oxygen species involved in both cellular signaling and oxidative stress, making its reliable detection essential in biological and environmental systems. Electrochemical sensing has emerged as a promising approach for H2O2 monitoring due to its high sensitivity, rapid response, and suitability for in situ analysis. This review provides a comprehensive overview of nanostructured metal oxide electrodes for non-enzymatic electrochemical detection of H2O2. The effects of material composition, nanostructure morphology, and synthesis strategies (particularly hydrothermal methods) on sensor performance are critically discussed. Special attention is given to our previously reported studies, enabling a consistent comparison of structure–property relationships under similar experimental conditions. Furthermore, the application of these sensors in plant stress analysis is examined, including both the monitoring of oxidative stress and the evaluation of stress mitigation strategies using metal oxide nanoparticles. The role of nanoparticles as reactive oxygen species scavengers and enhancers of plant antioxidant systems is highlighted, demonstrating their ability to reduce H2O2 levels and improve plant physiological status under adverse environmental conditions. Overall, this work emphasizes the dual functionality of nanostructured materials as both sensing platforms and active agents for stress mitigation, highlighting their potential in agricultural and environmental applications.