Structure and electrochemical detection of xenobiotic micro-pollutant hydroquinone using CeO₂ nanocrystals

In this study, cerium oxide nanocrystals (CeO₂ NCs) were synthesized by simple and cost effective precipitation method. The structural properties of the obtained CeO₂ NCs were characterized by means of X-ray diffraction (XRD) with Rietveld refinement analysis, Transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) confirms the presence of CeO₂ NCs. The structural properties confirmed the presence of cubic fluorite-type structure which is in agreement with the respective Inorganic Crystal Structure Database (ICSD) no. 156250. The hydroquinone (HQ) sensing of CeO₂ NCs/carbon paper (CP) modified electrode in 0.1 M phosphate buffer solution (pH = 7) was characterized using a cyclic voltammetric (CV) electrochemical technique. The CV curve exhibited redox peaks with a detection limit of 0.111 mM and the linear ranges (0.03-0.8 mM) with a sensitivity of 2.443 mA mM^-1 cm^-2 for HQ detection. Our results indicate that CeO₂ NCs modified on CP holds as a promising candidate for the electrochemical detection of toxic HQ.