Development of Selenium-Silica Nanocomposites By Sol-Gel Process Utilizing Three Different Reducing Agents and Its Characterization

Abstract

Nanocrystalline Selenium was synthesized within a silica matrix using a sol-gel method with high-purity SeO₂, ethyl alcohol, distilled water, and TEOS (Tetraethyl orthosilicate). This process encapsulated the selenium dioxide in the silica matrix, which was then reduced at about 100^°C using an oil bath. Three reducing agents were employed: acetone vapor, and sodium borohydride (NaBH₄) and hydrazine (N₂H₄) in liquid form. DSC-TGA analyses of the precursor mixture determined the crystallization temperature for selenium nanoparticle formation within the matrix to be around 100^°C. Post-heating phase analysis via XRD revealed hexagonal structures, with crystallite sizes between 33 and 43 nm determined using Debye-Scherrer's formula. Morphological studies showed irregular polygonal shapes with rough surfaces, with particulate sizes under 0.2µ for acetone vapor, around 0.1µ for hydrazine, and slightly over 0.1µ for sodium borohydride. Time variations were explored to observe phase and crystallite size changes. FTIR analysis was conducted for bonding assessment, revealing M-O coordination. The composite's absorbance was examined through UV-VIS spectroscopy, and its morphological attributes were investigated using FESEM analysis, complemented by EDX to determine elemental composition