Structural, Optical, and Magnetic Studies of the Metallic Lead Effect on MnO 2 -Pb-PbO 2 Vitroceramics.

MnO 2 -lead materials have attracted attention in their applications as electrodes. This work reports a detailed spectroscopic study of the compositional variation of MnO 2 -xLead vitroceramic materials with varied Pb contents. The concentration variation of lead and manganese ions issystematically characterized throughthe analysis of X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis), and electron paramagnetic resonance (EPR) spectroscopy.The MnO 2 -xLead samples consist of a vitroceramic structure with Pb, PbO, PbO 2 ,and Mn 3 O 4 crystalline phases. The introduction of higher Pb content in the host vitroceramic reveals the [PbO 6 ]→[PbO n ] conversion, where n = 3, 4, and the formation of distorted [MnO 6 ] octahedral units. The UV-Vis data of the samples possess the intense bands between 300 and 500 nm, which are due to the presence of divalent lead ions (320 nm) and divalent and trivalent manganese ions (420 and 490 nm, respectively) in the structure of glass ceramics. The EPR data show resonance lines located around g ~ 8 and 4.3, and a sextet hyperfine structure at g ~ 2, which isascribed to the Mn +3 and Mn +2 ions.