Structural, Optical, and Magnetic Studies of the Metallic Lead Effect on MnO2-Pb-PbO2 Vitroceramics

Simona Rada; Mihaela Unguresan; Mioara Zagrai; Adriana Popa

doi:10.3390/ma15228061

Structural, Optical, and Magnetic Studies of the Metallic Lead Effect on MnO₂-Pb-PbO₂ Vitroceramics

Materials (Basel). 2022 Nov 15;15(22):8061. doi: 10.3390/ma15228061.

Authors

Simona Rada^{1

2}, Mihaela Unguresan¹, Mioara Zagrai², Adriana Popa²

Affiliations

¹ Physics and Chemistry Department, Technical University of Cluj-Napoca, 400020 Cluj-Napoca, Romania.
² National Institute for Research and Development of Isotopic and Molecular Technologies, 400293 Cluj-Napoca, Romania.

Abstract

MnO₂-lead materials have attracted attention in their applications as electrodes. This work reports a detailed spectroscopic study of the compositional variation of MnO₂-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 MnO₂-xLead samples consist of a vitroceramic structure with Pb, PbO, PbO₂,and Mn₃O₄ crystalline phases. The introduction of higher Pb content in the host vitroceramic reveals the [PbO₆]→[PbO_n] conversion, where n = 3, 4, and the formation of distorted [MnO₆] 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.

Keywords: EPR; IR; MnO2-Pb-PbO2; UV–Vis; XRD.

Grants and funding

This paper was funded by the Romanian Ministry of Research, Innovation and Digitalization, CNCSIS-UEFISCDI by Nucleu program contract no. 19 35 01 01.