Controllable Synthesis and Electrochemical Behavior of Micro/Nano Octahedron Ceria

Abstract

Octahedron ceria crystals were fabricated by one-step hydrothermal synthesis without using any hard-template, with Ce(NO3)3·6H2O being raw materials and polyvinylpyrrolidone (PVP) being surfactant. The content of ethanol plays an important role in the morphology evolution of as-obtained CeO2. At 200°C, with the addition of ethanol into the water and by adjusting the ratio between ethanol and water from 1:3 to 3:1, the morphology of the as-obtained CeO2 changed from solid octahedron to hollow irregular particles. When the ratio between ethanol and water is 1:1, prolonging the reaction time from initial 6 h to 12 h and ultimate 48 h, the morphology of the as-obtained CeO2 growing from solid quasi-octahedron to regular octahedron, and then to hollow irregular particles. The electrochemical behavior of carbon paste electrode (CPE) modified by graphene/CeO2/CHIT nanocomposite membrane in 2.0 × 10–5 mol/L methylene blue (MB) containing 0.02 mol/L NaCl, and glassy carbon electrode (GCE) modified by MWNTs/CeO2/CHIT nanocomposite membrane in 1.0 mmol/L K3Fe(CN)6/K4Fe(CN)6 (1:1) containing 0.5 mol/L KCl as the supporting electrolyte were measured respectively. The electrochemical measurements were carried out by cyclic voltammetric (CV) and differential pulse voltammetry (DPV). The synergistic effects of as-synthesized micro/nano CeO2 and new carbon materials (MWNTs, graphene) on enhancing electrochemical signal were demonstrated, and a bright prospect of micro/nano octahedron CeO2 on electrochemical application can be seen from this paper.