Synthesis and Electrochemical Characterization of Silica-Manganese Oxide with a Core-shell Structure and Various Oxidation States

Abstract

Silica-manganese oxides with a core-shell structure were synthesized via precipitation of manganese oxides on the SiO 2 core while varying the concentration of a precipitation agent. Elemental analysis, crystalline property investigation, and morphology observations using low-and high-resolution electron microscopes were applied to the synthesized silica-manganese oxides with the core-shell structure. As the concentration of the precipitating agent increased, the manganese oxide shells around the SiO 2 core sequentially appeared as Mn 3 O 4 particles, Mn 2 O 3 +Mn 3 O 4 thin layers, and α-MnO 2 urchin-like phases. The prepared samples were assembled as electrodes in a supercapacitor with 0.1 M Na 2 SO 4 electrolyte, and their electrochemical properties were examined using cyclic voltammetry and charge-discharge cycling. The maximum specific capacitance obtained was 197 F g −1 for the SiO 2 -MnO 2 electrode due to the higher electronic conductivity of the MnO 2 shell compared to those of the Mn 2 O 3 and Mn 3 O 4 phases.

Sintesis MnO2 Lapisan Nipis Poros menggunakan Templat Silika Alumina-Aptes: Aplikasi Penjerapan Pewarna

“…Jalur yang berpusat pada 3474 cm -1 bagi silika alumina menunjukkan kehadiran getaran regangan kumpulan OH yang terikat kepada kumpulan silikon manakala jalur pada 1649 cm -1 menunjukkan kehadiran overtone dan gabungan getaran kekisi (Basila & Kantner 1967). Pada jalur 1079 cm -1 , menunjukkan wujudnya getaran regangan tidak simetri bagi Si-O-Si dalam SiO 2 , getaran regangan Si-O-Si wujud pada jalur 800, 732 dan 579 cm -1 dan getaran bengkokan wujud pada jalur 460 cm -1 (Antony et al 2014;Ryu et al 2011). Selain itu juga, tiada jalur yang menunjukkan kewujudan alumina pada permukaan sebatian kerana ion aluminium tersebar di seluruh kekisi.…”

SINTESIS MnO2 NANOBUNGA POROS MENGGUNAKAN TEMPLAT SILIKA-APTES

“…Manakala jalur pada 1650 cm -1 menunjukkan bengkokan kumpulan silanol [25]. Pada jalur 1079 cm -1 , menunjukkan wujudnya getaran regangan tidak simetri bagi Si-O-Si dalam SiO 2 , getaran regangan Si-O-Si wujud pada jalur 975 dan 800 cm -1 , dan getaran bengkokan wujud pada jalur 471 cm -1 [25,26]. Selepas refluks dilakukan, spektrum silika-APTES menunjukkan kehadiran jalur baru di dalam kawasan 3290-3000 cm -1 dimana ini merujuk kepada kehadiran getaran regangan kumpulan NH 2 .…”

Ultrafine Mn3O4 nanowires synthesized by colloidal method as electrode materials for supercapacitors with a wide voltage range

“…Up to now, many types of pseudo-capacitive electrode materials have been discovered, such as ruthenium oxides [13][14][15] and manganese oxides [16][17][18][19].…”

“…Ruthenium oxides are regarded as ideal pseudo-capacitor electrode materials due to their high specific capacitance of 760 F g -1 , good electrical conductivity and cycle stability [15]. However, they are expensive, toxic and often difficult to prepare [20].…”