Advances in Smart Electrocatalytic Sensors Based on Vertically Aligned Nanostructures for Agricultural Pesticide Monitoring

Recent advances in the synthesis of nanostructures and nanomaterials have catalyzed transformative developments across multiple scientific domains. Among these, vertically aligned nanostructures (VANs) have attracted considerable attention due to their unique architectural features─such as high surface area and roughness, unimpeded charge transport, and large aspect ratio. Specifically, their applications in the detection of agricultural pesticides have gained increasing importance amid rising global pesticide consumption. Such emerging environmental contaminants pose serious ecological and health risks due to their persistence and bioaccumulation potential. This Perspective provides a comprehensive overview of recent progress in electrochemical sensors based on nanostructured materials for pesticide detection. The metal oxide nanostructure-based sensor usually gives the lowest detection limit compared with other nanomaterial-based sensors. Emphasis is given to both binder-free (directly grown) and binder-based (immobilized) nanostructures integrated onto working electrodes, highlighting their synthesis strategies, physicochemical properties, and performance in electrochemical sensing. Binder-free sensors have a superior detection limit compared to binder-based sensors. We systematically evaluate the comparative advantages, limitations, and mechanistic insights governing the sensing behavior. Furthermore, the review explores state-of-the-art synthetic methodologies for fabricating nanostructures tailored to sensor applications. Finally, we propose a future perspective on the development of biobased VANs integrated into portable and smart electrochemical sensing platforms. These next-generation sensors are envisioned to offer high sensitivity, long-term operational stability, and ultralow detection limits, enabling real-time monitoring of hazardous environmental pollutants directly at their sources.