Size and surface-engineered BiVO4 catalytic smooth spheres for efficient electrochemical detection of bifenox herbicide

Abstract

Synthesis of smooth-surfaced BiVO₄ semiconducting particles with periodic size control was achieved under hydrothermal conditions with long carbon chain oleic acid as an additive in weak organic acid and methanol as solvents for bifenox, a nitrodiphenyl ether herbicide detection. BiVO₄ obtained from conventional hydrothermal synthesis has a rough surface and hierarchical morphology. The current method provides a smooth and tuned particle size. The structure and morphology of the derived BiVO₄ under various concentrations of oleic acid were characterized using X-ray diffraction, Raman, SEM, and TEM analyses. The XPS analysis was carried out to identify the elements with their oxidation states. A glassy carbon electrode (GCE) modified with BiVO₄ nanoparticles was applied to determine bifenox electrochemically. Since bifenox is a nitroaromatic herbicide, the electrochemical parameters for its detection were obtained using nitrophenol as a model compound and cyclic voltammetry (CV). Sensing characterizations are carried out with electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and amperometry techniques. Bifenox undergoes electrochemical reduction at −500 mV on a BiVO₄ modified electrode, and the limit of detection (LOD) was found to be 0.3 nM. The change in the size and the morphology of the synthesized samples collected after the experiment were investigated using XRD and SEM analyses. Hence, the practical accessibility of the present BiVO₄-modified GCE is good for the environmental analysis of bifenox herbicide.