Synthesis of CeO2/reduced graphene oxide nanocomposite for electrochemical determination of ascorbic acid and dopamine and for photocatalytic applications

In this study, the CeO2/reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method. Structure and morphology of the synthesized nanocomposite were characterized by X-ray diffraction and scanning electron microscopy. Raman spectroscopy and X-ray photoelectron spectroscopy were used to quantify the concentration of oxygen vacancies. Compared with the bare glassy carbon electrode (GCE) and CeO2-modified GCE, the CeO2/rGO electrode exhibited an excellent electrochemical activity toward the oxidation of ascorbic acid and dopamine. Increased concentration of oxygen vacancies coupled with the introduction of rGO as a matrix in the composite resulted in the improvement of the conductivity of the nanocrystals, thereby leading to a faster charge transfer. The photocatalytic properties of CeO(2)and CeO2/rGO nanocomposite were evaluated using the degradation of methylene blue under UV-vis light irradiation. Degradation rate constant was determined to be 0.0011 min(-1) and 0.0035 min(-1) with CeO(2)and CeO2/rGO photocatalyst, respectively. The CeO2/rGO nanocomposite exhibited a significant increase in the photoactivity compared with CeO2 because of the unique properties of rGO in suppressing the recombination of photogenerated charge carriers. (C) 2019 Elsevier Ltd. All rights reserved.