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).

Trace determination of radioactive waste, especially Ce, by electrochemical methods has rarely been attempted. Ce 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 Ce 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 Ce 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 Ce in acetate buffer solution (ABS, pH 4.0 ± 0.05) at a scan rate of 50 mV s 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 ( 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 Ce, (iv) strongly pH-dependent, and (v) favored Ce sensing only at pH 4.0 ± 0.05. Impedance spectroscopy results indicated that the GNB-modified-CF electrode was more conductive (1.38 × 10 S m) 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 Ce onto the electrode surface and the size of the electrode material. Ce nanobuds increased from 35-40 to 50-55 nm without changing their morphology. The obtained results provide an insight into the determination of Ce to develop an electrochemical device with low sensitivity.