Sensitive and selective chloroform sensor using Fe2O3 nanoparticle-decorated ZnO nanorods in an aqueous solution

Abstract

Liquid-phase volatile organic compounds must be monitored to protect the environment and humans from their toxic effects. This work describes the fabrication, characterization, and performance analysis of as-grown ZnO and Fe2O3/ZnO nanorod electrodes in Fe2O3 colloidal suspension at different soaking times (1, 3, 5, and 7 h). Morphology and phase were analyzed by field-emission scanning electron microscopy and X-ray diffraction, respectively. Results confirmed the successful fabrication of as-grown ZnO and Fe2O3/ZnO electrodes with diameters of 52–90 nm for ZnO nanorods and 12–27 nm for Fe2O3 particles. The chloroform-detection abilities of these nanorod electrodes were assessed through their electrochemical properties by cyclic voltammetry and three-electrode current–voltage method. The Fe2O3/ZnO nanorod electrode soaked for 5 h in Fe2O3 colloidal suspension showed the highest sensitivity and lowest limit of detection of 4.501 µA cm−2 mM and 0.60 µM, respectively, within the linear dynamic range of 10 µM to 10 mM, whereas that soaked for 5 h exhibited reproducible signals for the five consecutive electrodes. Therefore, the Fe2O3/ZnO nanorod-modified electrode can be used for low-cost and simple chloroform detection.