Surface and morphology analyses, and voltammetry studies for electrochemical determination of cerium(iii) using a graphene nanobud-modified-carbon felt electrode in acidic buffer solution (pH 4.0 ± 0.05)

Pavithra V Ravi; Daniel T Thangadurai; Kasi Nehru; Yong Ill Lee; Devaraj Nataraj; Sabu Thomas; Nandakumar Kalarikkal; Jiya Jose

doi:10.1039/d0ra07555h

Surface and morphology analyses, and voltammetry studies for electrochemical determination of cerium(iii) using a graphene nanobud-modified-carbon felt electrode in acidic buffer solution (pH 4.0 ± 0.05)

RSC Adv. 2020 Oct 9;10(61):37409-37418. doi: 10.1039/d0ra07555h. eCollection 2020 Oct 7.

Authors

Pavithra V Ravi¹, Daniel T Thangadurai¹, Kasi Nehru², Yong Ill Lee³, Devaraj Nataraj⁴, Sabu Thomas⁵, Nandakumar Kalarikkal⁵, Jiya Jose⁵

Affiliations

¹ Department of Nanoscience and Technology, Sri Ramakrishana Engineering College, Affiliated to Anna University Coimbatore - 641 022 Tamilnadu India danielt@srec.ac.in.
² Department of Chemistry, Anna University - Bharathidasan Institute of Technology Tiruchirappalli - 620 024 Tamilnadu India.
³ Department of Chemistry, Changwon National University Changwon 641-773 South Korea.
⁴ Department of Physics, Bharathiar University Coimbatore - 641 046 Tamilnadu India.
⁵ International and Inter-University Centre for Nanoscience and Nontechnology, Mahatma Gandhi University Kottayam - 686 560 Kerala India.

Abstract

Trace determination of radioactive waste, especially Ce³⁺, by electrochemical methods has rarely been attempted. Ce³⁺ is (i) a fluorescence quencher, (ii) an antiferromagnet, and (iii) a superconductor, and it has been incorporated into fast scintillators, LED phosphors, and fluorescent lamps. Although Ce³⁺ has been utilized in many industries due to its specific properties, it causes severe health problems to human beings because of its toxicity. Nanomaterials with fascinating electrical properties can play a vital role in the fabrication of a sensor device to detect the analyte of interest. In the present study, surfactant-free 1,8-diaminonaphthalene (DAN)-functionalized graphene quantum dots (DAN-GQDs) with nanobud (NB) morphology were utilized for the determination of Ce³⁺ through electrochemical studies. The working electrode, graphene nanobud (GNB)-modified-carbon felt (CF), was developed by a simple drop-coating method for the sensitive detection of Ce³⁺ in acetate buffer solution (ABS, pH 4.0 ± 0.05) at a scan rate of 50 mV s^-1 using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV and DPV studies validated the existence of distinctive peaks at approximately +0.20 and +0.93 V (vs. SCE), respectively, with a limit of detection of approximately 2.60 μM. Furthermore, electrochemical studies revealed that the GNB-modified-CF electrode was (i) stable even after fifteen cycles, (ii) reproducible, (iii) selective towards Ce³⁺, (iv) strongly pH-dependent, and (v) favored Ce³⁺ sensing only at pH 4.0 ± 0.05. Impedance spectroscopy results indicated that the GNB-modified-CF electrode was more conductive (1.38 × 10^-4 S m^-1) and exhibited more rapid electron transfer than bare CF, which agrees with the attained Randles equivalent circuit. Microscopy (AFM, FE-SEM, and HR-TEM), spectroscopy (XPS and Raman), XRD, and energy-dispersive X-ray (EDX) analyses of the GNB-modified-CF electrode confirmed the adsorption of Ce³⁺ onto the electrode surface and the size of the electrode material. Ce³⁺ nanobuds increased from 35-40 to 50-55 nm without changing their morphology. The obtained results provide an insight into the determination of Ce³⁺ to develop an electrochemical device with low sensitivity.