Tem 3010

The crystal phases for the samples were examined using X-ray diffraction (XRD, Bruker, D8 ADVANCE, Karlsruhe, Germany) with Cu K_α radiation (λ = 1.5406 Å). Furthermore, transmission electron microscopy (TEM) (JEOL, TEM-3010, Tokyo, Japan) with an acceleration voltage of 80 kV was utilized to examine the microstructures for the as-prepared MnO₂-based electrodes. The Brunauer-Emmett-Teller (BET) surface area, Barrett-Joyner-Halenda (BJH) mesopore area, t-plot micropore area, and N₂ adsorption-desorption isotherms were measured with a Micrometrics ASAP 2020 instrument.

Zinc blende CdS nanoparticles were prepared following previously published methods [48 ,49 ]. For this, 0.126 g CdO (0.98 mmol), 2.02 g oleic acid (7.1 mmol), and 12 mL ODE were added into a three-neck flask. The mixture was degassed for 10 min in the presence of N₂ gas, and the temperature was raised to 300 °C. At this stage, 2 mL of S-ODE solution (0.25 M) was swiftly added to the flask, and the temperature was adjusted to 250 °C. The reaction was kept at this temperature for 5 min to allow for the growth of nanoparticles. The reaction was stopped by removing the heating mantle, and the solution was left to cool down at room temperature. Finally, the particles were washed by precipitating through acetone and methanol and resuspended into chloroform. Figure 1 depicts the average diameter of CdS nanoparticles taken with TEM (TEM 3010 JEOL Ltd., Tokyo, Japan) along with variability.