Co3O4 spinel nanoparticles decorated graphite electrode: Bio-mediated synthesis and electrochemical H2O2 sensing. (10th October 2017)

• Record Type: Journal Article
• Authors: Das, Raj Kumar; Golder, Animes Kumar
• Is Part Of: Electrochimica acta. Volume 251(2017)
• Page Start: 415
• Page End: 426
• Publication Date: 2017-10-10
• Subjects: Green synthesis -- Spinel cobalt oxide -- Ferromagnetism -- Cyclic voltammetry -- Electrochemical sensing; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.08.122
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Extracellular synthesis of single crystalline Co3 O4 NPs using analytes present in Sechium edule . Weak ferromagnetic Co3 O4 NPs of 31.25 nm average diameter tailored on carbon paste electrode for H2 O2 sensing. Co3 O4 NPs surface concentration 5.92 × 10 −13 mol/cm 2 for Co(OH)2 /Co3 O4 and, Co3 O4 /CoOOH redox couple. H2 O2 detection limit 0.0217 μM and sensitivity 65.32 nA/μM/cm 2 was invariant by electroactive species. Abstract: The Co3 O4 NPs were successfully synthesized by a green synthesis pathway using the analytes extracted from Sechium edule, the fruit of a perennial climber. The analytes, mostly, ascorbic acid, mediated CoOOH transformation to Co(OH)2 and, CoOOH was abundant with Co3 O4 NPs in the control condition without these analytes. The structure and morphology of Co3 O4 NPs were determined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Atomic force microscopy (AFM), Field emission scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM). The pure Co3 O4 NPs confirmed weak ferromagnetic properties. TEM images showed that the Co3 O4 NPs have an average diameter size of 31.79 nm. The Co3 O4 NPs were tailored on a graphite electrode with an average concentration of 5.92 × 10 −13 mol/cm 2 to develop a non-enzymatic H2 O2 sensor in a phosphate buffer media (pH 7.2). The cyclic voltammetry (CV) technique within the − Ecat = 0.5 to −0.5 V vs. Ag/AgCl showed a low H2 O2 reduction peak at −0.117 V with a quasi-reversible electrochemical system. The modified electrode was exhibited a quick amperometric response (<5 s), a low limit of detection (LOD) of H2 O2 of 0.0217 μM, and a high electrode sensitivity of 65.32 nA/μM/cm 2 and reproducibility (relative standard deviation 3.06%). No alteration of the amperometric responses was noted in the presence of common interferents.