Abstract
A single phase rhombohedral LaCoO3 perovskite is prepared by the microwave-assistant citrate method. The as-synthesized perovskite is applied as a facile sensor for hydrazine determination in aqueous 1 M KOH by using electrochemical techniques such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The cyclic volyammogram of LaCoO3 modified glassy carbon electrode (GC/LaCoO3) show a well-defined hydrazine oxidation peak of a current, I-p, equals 1.71 mA.cm(-2) at an oxidation peak potential, E-p, of +518.8 mV vs. Ag/AgCI. On the other hand, no hydrazine oxidation is observed at modified GC electrodes with other lanthanum-transition metals perovskites, LaBO3 (B is Ni, Mn, Cr, or Fe). EIS data showed a reduction of the charge-transfer resistance value from 220.9 to 3.8 Omega . cm(2) by casting LaCoO3 on GC electrode surface, reflecting the powerful electrocatlaytic activity of LaCoO3 towards the hydrazine oxidation. The presented sensor has two linear responses over hydrazine concentration ranges 0.1-15 and 20-60 mM, with sensitivity values of 5.61 mA cm(-2). M-1 and limit of detection (LOD) value of 0.15 nM, respectively. The sensor exhibits a high stability, excellent reproducibility and accepted anti-interferences ability for various inorganic ions and organic compounds. (C) 2019 Elsevier B.V. All rights reserved.