Synthesis and Characterization of Al–Doped Manganese Oxide Nanoparticles

Aluminum-doped manganese oxide (Al-doped MnO₂) nanoparticles were successfully synthesized using the chemical precipitation method. Manganese chloride tetrahydrate (MnCl₂·4H₂O) and aluminum sulfate (Al₂(SO₄)₃) were utilized as precursor materials, with sodium hydroxide (NaOH) serving as the precipitating agent. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and UV-Vis spectroscopy were employed to analyze the structural, morphological, and optical properties of the synthesized nanoparticles. XRD analysis confirmed a tetragonal MnO₂ phase, with crystallite sizes ranging from 49.75 nm to 92.71 nm. SEM and TEM images revealed that the nanoparticles exhibited a uniform morphology with slight agglomeration, with individual particle sizes ranging from 13.34 nm to 22.23 nm. The incorporation of aluminum was validated through EDX, which demonstrated a homogeneous distribution of dopant atoms within the MnO₂ matrix. UV-Vis spectroscopy indicated a direct bandgap of 3.79 eV, suggesting significant optoelectronic applicability. The enhanced electrical conductivity, structural stability, and catalytic activity of Al-doped MnO₂ highlight its potential for diverse applications in energy storage devices, supercapacitors, and photocatalysis. This study underscores the effectiveness of aluminum doping in modifying the physicochemical properties of MnO₂, paving the way for its integration into next-generation electronic and catalytic systems.