Charge transfer effects and O2- vacancies in pure CuO nanofibers and enriched with 3.0% Mn

This research shows the relationship between oxygen vacancies and the charge transfer effects generated from the synthesis process using the electrospinning method in an uncontrolled atmosphere for copper oxide nanofibers (CuO NFs) pure and enriched with 3.0% Mn. The thermal measurements obtained through TGA-DSC allowed finding the calcination temperature and obtaining the tenorite structure with monoclinic phase at 700 °C. In addition, the combination of x-ray photoelectron spectrum (XPS) with the multiplet calculation using Cowan's codes suggests that the charge transfer effects play an important role in CuO NFs. After XPS analysis was possible to determine the presence of oxygen vacancies (Vo) and oxygen adsorbed (Ao) in the XPS O 1s region placed at 532 eV. The synthesized materials show a mixture of oxides, and a single oxidation state for Cu3+ in a superlattice according to the selected area electron diffraction (SAED) analysis. Finally, the CuO NFs enriched with 3.0% show the presence of Mn4+ and Mn3+ according to the XPS Mn 2p region analysis.