جستجوی مقالات مرتبط با کلیدواژه « mno2 » در نشریات گروه « مواد و متالورژی »

Mesoporous manganese oxide nanoparticles were prepared using SBA-15 hard silica template (SBA-MnO2) and were investigated as electrode material for electrochemical pseudocapacitors. Also, for comparison, mesoporous manganese oxide nanoparticles were prepared using pluronic P123 copolymer as a soft template (P123-MnO2). Structural and morphological characterizations of the prepared manganese oxide nanostructured materials were conducted using X-ray diffraction (XRD), nitrogen absorption/desorption test, scanning electron microscope (SEM) and transmission electron microscope (TEM). In addition, electrochemical investigations of the electrode materials were performed using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) examinations. The results showed that the SBA-MnO2 active material has a higher specific capacitance (1200 F g-1 in a current density of 1 A g-1) than the P123-MnO2 material (1200 F g-1 in a current density of 1 A g-1) due to its higher specific surface area and more porous structure. Therefore, the mesoporous SBA-MnO2 active material can be introduced as a potential electrode material for high-performance electrochemical capacitors.

Alumina-mullite-zirconia composites were prepared by the reaction sintering method between alumina and zircon powders and the effect of two additives (chromium oxide and manganese oxide)were investigated on their properties. 2 and 4 wt% of each oxide were added to the raw material composition and after pressing, the samples were sintered at 1630°C. The results showed that chromium oxide decreased the density, strength, and hardness of the samples, while manganese oxide increased the density, strength, and hardness. The microstructure of the composite made with Chromium oxide was also uniform and homogeneous and the grain size was relatively smaller; whereas, unlike the improved mechanical properties with manganese oxide, this additive resulted in the growth of grains. The boundary phase which was formed between the grains in the samples containing manganese oxide was also investigated. The effect of chromium oxide and manganese oxide on the composition of the final phases (formation of mullite and zirconia) was different.