XPS investigation of F-doped MnO2 nanosystems fabricated by plasma assisted-CVD

Supported Mn(IV) oxide nanomaterials were prepared by plasma assisted-chemical vapor deposition from Ar/O2 plasmas starting from a fluorinated Mn(II) β-diketonate diamine adduct. Under the adopted conditions, the target compound served as a single-source molecular precursor for the obtainment of MnO2 nanosystems uniformly doped with fluorine. The overall F content in the target materials, composed of phase-pure β-MnO2, could be tailored as a function of the deposition temperature from 100 to 400 °C, a result of particular importance in view of photocatalytic and gas sensing applications. In the present study, attention is specifically devoted to the investigation of a representative specimen by means of x-ray photoelectron spectroscopy. Besides the wide scan spectrum, a detailed analysis of C 1s, O 1s, Mn 2p, Mn 3s, and F 1s photoelectron peaks is presented and discussed. The analyses reveal the formation of MnO2 free from other manganese oxides, with fluorine present in different chemical states, i.e., lattice F plus traces of precursor residuals at the system surface.