Green Synthesis, Hybridization of SiO₂ by Alkaline -Acid Leaching Method and their Optical and Structural Properties Using Rice Husk and <i>Anogeissus leiocarpus</i> Extract

Abstract

Silicon oxide is widely used as a thin film to improve the surface properties of materials, because it is of anti-resistance, hardness, corrosion resistance, dielectric, optical transparency and high delivery property etc. Therefore. Recent growing interest and efforts of scientists in this area are due to vitality in achievement of a better quality of life and health care for human beings, designing novel methods of making them more effective through hybridization with silver nanoparticles. Hence the need for nanoparticles capable of transmitting light with an ‘enhanced’ optical property for optoelectronics. In this study, silica was extracted from rice husk ash (RHA) using alkaline/acid leaching method, the AgNps was synthesized from Anogeissus leiocarpus extract using water extraction process, while the hybridization of silica with AgNps was carried out using in-situ and co-mixing method. Characterization was achieved using UV-Visible to confirmed the presence of silica at 290 nm, 291 nm, and 295 nm at different time intervals of 0, 60, 90. Changes in intensities of the bands indicate perfect hybridization with an enhancement in optical property. The XRD pattern of the silica-silver nanoparticles showed crystalline peaks at 2θ = 22.0o, 26.5o,29.5o 41o, which have been keenly indexed as face centred cubic Ago nanocrystals arising from Anogeissus leiocarpus extract. The increase in absorbance value of silica from (0.5 to 1.45, 1.50 respectively) confirms the improvement in optical properties of silica due to presence of AgNPs. The SEM analysis revealed the cap shaped spherical morphology and uniform size distribution of the nanohybrids within the range of 18.20 nm. Capping obtained is an evidence of organic matter in the plant extract. The percentage elemental compositions of Ag, Si, C and O in the nanohybrids were revealed by EDX analysis where Ag and Si are dominant. Therefore, silica-silver nanocomposite can be used as improved raw material in optical, ceramics and other relevant industries.