Highly Efficient Construction of Electrochemical Sensing Device Based on Metal/Semiconductor Heterostructure with Build-In Electric Field for Ultrasensitive Detection of Dichlorvos

The development of a cost-effective and environmentally friendly nano-heterostructure electrochemical sensing material for analyzing hazardous substances is a critical and challenging task. Variations in Fermi levels (Ef) create a driving force for electron flow at the metal/semiconductor interfaces, leading to the formation of a built-in electric field that enhances charge transfer within the electrochemical sensing layer. In this study, a hierarchical nanoflower-shaped Co3O4/SnO2/polyaniline (Co3O4/SnO2/PANI) heterostructure with a built-in electric field was successfully synthesized using a hydrothermal method and chemical oxidative polymerization. The electrochemical biosensing platform based on Co3O4/SnO2/PANI nanoflowers for detecting dichlorvos through enzyme inhibition principle exhibited excellent analytical performance, including a wide detection range (4.53x10(-13) M similar to 4.53x10(-7) M), a low detection limit (12.6 fM), good anti-interference capability, acceptable reproducibility, and recoveries ranging from 92.4 % to 105.7 %. These results were attributed to the exceptional physicochemical properties of the heterostructure, such as excellent electronic conductivity, enhanced charge transfer, a large electrochemical active area due to its unique morphology, and high electrocatalytic property of the heterojunction. This research serves as a valuable reference for designing advanced electrochemical biosensing platforms for hazardous substances in the realms of food safety and environmental monitoring.