Preparation and characterization of manganese oxide nanoparticles-coated Albizia procera derived carbon for electrochemical water oxidation

This work reports the preparation of manganese oxide nanoparticles on Albizia procera derived carbon (MnO_xNPs-C) for electrochemical water oxidation, by a simple thermal decomposition method. Morphological variations, formation of crystalline structure, elemental, and chemical analyses were studied using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS), respectively. The SEM analysis showed that the manganese oxide nanoparticles are well dispersed over the carbon. The amount of manganese oxide nanoparticles increases by increasing the amount of precursor. XRD results showed the single-phase formation of the Mn₃O₄, and Mn₃O₄ along with MnO phase formation at low and high amount of the precursor materials, respectively. The chemical composition and the constituent elements of the prepared samples were also confirmed by EDS and XPS, consistent with the XRD results. Thermogravimetric and differential scanning calorimetry (TGA/DSC) analysis was used to study the thermal decomposition behavior of the as-prepared MnO_xNPs-C and its precursors. Four different samples (prepared catalysts) were tested for the optimization of electrocatalytic activities towards water oxidation. The sample prepared using the highest amount of manganese precursor shows good stability and best catalytic performance for water oxidation.