Low-temperature synthesis of doped MnO2–carbon dots nanocomposite: an analysis of nanostructure and electrical properties

Abstract

The synthesis of δ-MnO₂, δ-MnO₂ carbon dots nanocomposite, and Fe/Cu-doped δ-MnO₂ carbon dots nanocomposite has been successfully carried out through a stirring process at room temperature and 80 °C. The synthesized powder shows a low crystallization determined through XRD and TEM analysis. Furthermore, the carbon dots are well attached to MnO₂ performing a core–shell composite material, while the doping ions Fe and Cu were incorporated into the matrix substitute Mn in the MnO₆ octahedron, although potassium ions were also detected. The manganese possess an oxidation state of + 3 and + 4, which promotes the oxygen vacancy creation \({V}_{\mathrm{O}}^{\cdot\cdot}\) denoting the conductivity decrease.