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 $${V}_{\mathrm{O}}^{\cdot\cdot}$$ V O · · denoting the conductivity decrease.