Open AccessMnO2 Nanoparticles Prepared by Alternating Monopolar Arrangement Electrolysis and Their Electrochemical Performances
Author(s) -
W. Widiyastuti,
Heru Setyawan,
Mahardika F. Rois,
Hariyati Purwaningsih,
Puspita Nurlilasari
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/778/1/012020
Subject(s) - cyclic voltammetry , materials science , electrolysis , amorphous solid , scanning electron microscope , nanoparticle , electrocatalyst , crystallinity , specific surface area , electrochemistry , chemical engineering , adsorption , manganese , electrode , analytical chemistry (journal) , nanotechnology , chemistry , crystallography , catalysis , composite material , chromatography , metallurgy , organic chemistry , electrolyte , engineering
Manganese dioxide nanoparticles have been successfully synthesized by the electrolysis method using 4-pairs carbon electrode in the alternating monopolar arrangement. The advantage of the arrangement is a significant increase in the product yield compared to the single pair electrodes. KMnO 4 solution in pH 0.2 and 9 were used as precursor and electrolyzed for thirty minutes at a temperature of 60 °C. The generated particles resulted from electrolysis in pH 0.2 (MnO 2 -A) and in pH 9 (MnO 2 -B) were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen adsorption-desorption isotherms to examine their crystallinity, morphology, and the specific surface area. The α-MnO 2 was observed for MnO 2 -A particles and amorphous for MnO 2 -B particles. The particles size of MnO 2 -A was larger than that of MnO 2 -B with the specific surface areas of 396 and 98 m 2 /g, respectively. The higher surface area of MnO 2 -A corresponding to the channel pore of short rod-like morphology. On the other hand, MnO 2 -B contributed to the spherical particles. The measurements of cyclic voltammetry (CV) were also carried out to measure their specific capacitances and their performance for oxygen reduction reaction (ORR) electrocatalyst. MnO 2 -A exhibited higher specific capacitance of 13.57 F/g compared to MnO 2 -B that only had 3.62 F/g. In addition, MnO 2 -A also gave better performance as ORR electrocatalyst measured in O 2 -saturated 0.6 M KOH resulted in 2.69 transferred electron number per oxygen molecule.