Facile synthesis of CeO2-SnO2 nanocomposite for electrochemical determination of L-cysteine

摘要

CeO2-SnO2 nanocomposites were synthesized by simple chemical precipitation method. The composites were characterized by XRD, UVevis, SEM, FE-SEM, HR-TEM, FT-IR and FT-Raman. X-ray diffraction result confirms the structure with good crystalline and size of the nanocomposites. HR-TEM results revealed formation of nanocomposite in spherical shape with less than 10 nm size and highly homogeneous. X-ray photoelectron spectroscopy confirmed the chemical composition and different ionization states of Ce3+/Ce4+, Sn4+ and O1s. Functional groups of nanocomposites were identified using FT-IR spectroscopy. FT-RAMAN spectra were used to identify the Raman shift, which supported the formation of nanocomposite. Thermal stability and phase changes of CeO2-SnO2 nanocomposite were characterized by TG and DTA. Paramagnetic property of the nanocomposite at room temperature was studied by EPR technique. The results of cyclic voltammetry and amperometry studies demonstrated the electrocatalytic activity of CeO2-SnO2 nanocomposites towards L-cysteine oxidation. The electrochemical studies showed that CeO2-SnO2 composite detects L-cysteine linearly over a concentration range from 0.016 x 10(-3)M to 2 x 10(-3) M. The electrochemical sensor showed high sensitivity of 186.34 mu A mM(-1) cm(-2) with lower detection limit of 0.016 x 10(-3) M. Moreover, the sensor results showed good selectivity, excellent stability and reproducibility of the CeO2-SnO2 nanocomposites as a promising candidate for L-cysteine sensing. (C) 2019 Elsevier B.V. All rights reserved.