Structural, Morphological, and Optical Characterisation of Tin Dioxide Powders with Nominal Manganese Additions Prepared by an Aqueous Sol–Gel Route

Abstract

Tin dioxide (SnO₂) powders designated as undoped or as nominally containing 0.2 or 0.4 wt% manganese were prepared by an aqueous sol–gel method and examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–visible spectroscopy. The diffraction patterns display reflections consistent with tetragonal rutile SnO₂, and the micrographs show irregular, agglomerated particulate features. A spectrum assigned to a Mn-containing specimen includes signals attributed to Sn, O, and Mn. The crystallite-size values tabulated for the three nominal groups are 76.87, 212.02, and 76.90 nm, but peak-broadening information required to reproduce them is unavailable. The synthesis designations of 0.2 and 0.4 wt% Mn are inconsistent with the 2 and 4 wt% labels in the analytical figures. Furthermore, the tabulated lattice parameter for undoped SnO₂ conflicts with its indexed diffraction peak, and the reported optical-gap estimates lack supporting fit data. Accordingly, the measurements document rutile-compatible diffraction and qualitative morphology, whereas manganese-dependent structural and optical changes cannot be quantified reliably.