Sensitive electrochemical detection of 4-nitrophenol through Copper doped CeO2 nanoparticles

Abstract

In this study, we developed an electrochemical sensor for sensitive detection of 4-NP in solution by using polyol-assisted co-precipitation process prepared copper doped cerium oxide nanoparticles (CeO2:Cu NPs). Phase purity, crystal structure, and morphology of the as-prepared nanoproduct were examined by X-ray diffraction and transmission electron microscopy images. Chemical composition was determined by energy dispersive x-ray analysis(EDX). UV/Visible spectrum was measured to determine the optical absorption properties and bandgap energies of the material. The prepared CeO2:Cu NPs were pasted on a glassy carbon electrode(GCE) to measure the electro-catalytic performance and further examining their sensing application through determining the 4-nitrophenol (4-NP) concentrations. The performance of the constructed electrode was assessed by cyclic voltammetry(CV) and electrochemical impedance spectroscopic(EIS) methods. The Cu doped CeO2 NPs exhibited demonstrated excellent electrochemical performance in the presence of 4-NPs in a 10 pH phosphate buffer solution (PBS). The voltammetry-acquired kinetic evidence shows that 4NP electro-oxidation is a strictly diffusion-controlled process and that four electrons are involved in the reaction mechanism. The constructed CeO2:Cu/GCE illustrated a high linearity range from 7.18-5000µL, a good detection limit (7.18 µL), with high sensitivity 1.4 μA\u202fmmol−1\u202fL. The reproducibility of the fabricated electrode was also monitored through nine consecutive CV cycles to measure their stability.