Preparation of the CeO2/NG/NiCo(OH)x Composite Electrode for Ultrasensitive Fenitrothion Detection

Abstract

Fenitrothion is one of the most commonly used organophosphorus pesticides to combat pest invasion and increase crop yields. However, since the toxicity of fenitrothion residues after its use poses a serious threat to the surrounding environment, rapid and sensitive detection of the pesticide fenitrothion will help prevent pesticide poisoning and its overspray. In this study, CeO₂/NiCo(OH)_x nanomaterials were synthesized in situ by a two-step reflux method using a cobalt(II)-based metal–organic framework ZIF-67 as a precursor. Nitrogen-doped graphene (NG) was then combined with it by ultrasonic treatment to prepare CeO₂/NG/NiCo(OH)_x composites. This composite can be used for the direct detection of the insecticide fenitrothion. The study extensively characterized the composites using SEM, XRD, and EDS, confirming their unique nanostructures and elemental compositions. The experimental results showed that the CeO₂/NG/NiCo(OH)_x/GCE sensing electrode exhibited a linear response in the concentration ranges of 0.1–1.0 and 1.0–10.0 μM, respectively, with a detection limit of 5.0 nM and recoveries ranging from 97.8 to 106.7% for fenitrothion, which makes it suitable for the ultrasensitive detection of fenitrothion in real environmental samples. The sensor shows ultrasensitive detection of fenitrothion, which will be of significant impact and wide interest to users and farmers in agricultural safeguarding and environmental protection.