Electrochemical deposition and plane-wave periodic DFT study on Dy2O3 nanoparticles and pseudocapacitance performance of Dy2O3/conductive polymer nanocomposite film

In view of the current trend to apply green chemistry to product development and to reduce the use of toxic materials, this work is based on the optimization of a green cathodic electrodeposition method and followed heat treatment to prepare nanostructured Dy2O3, in an aqueous solution of dysprosium (III) nitrate hydrate. Prepared Dy2O3 nanoparticles have been characterized by different analysis such as FT-IR spectroscopy, thermogravimetric-differential scanning calorimetry (TG-DSC), field-emission scanning electron microscopy (FE-SEM) and X-Ray diffraction (XRD). Not only from the XRD spectrum but also using the Nelson-Riley functions, various mechanical parameters referring to Dy2O3 nanoparticles, e.g. particle size, texture coefficient, strain, and lattice constant, were determined. To understand more details about the bulk structure and electronic properties of Dy2O3, periodic plane-wave density functional theory calculations have been conducted by Quantum Espresso code. Dy2O3 exhibits an indirect band gap of 2.0 eV was computed using first-principle density functional theory (DFT) calculations. For improving electrochemical properties of the poly ortho aminophenol (POAP), we fabricated POAP/Dy2O3 films by electro-polymerization of POAP in the presence of electrosynthesized Dy2O3 with porous structure, to serve as the active electrode for electrochemical supercapacitor. In terms of electrochemical methods, galvanostatic charge-discharge experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. The enhanced supercapacitor behavior observed for the prepared composite film can be attributed to synergistic effect existing between Dy2O3 nanoparticles and the conductive polymer. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.