PREPARATION OF SILVER-DOPED RICE HUSK SILICA COMPOSITES USING THE SOL-GEL METHOD

Abstract

Silver-doped rice husk silica composites were created using the sol-gel method. Silver nitrate and rice husks were used as the resources. The composites were sintered at 850°C and then characterised using Fourier transform Infrared Spectroscopy (FTIR), X-ray diffractometry (XRD) coupled with a Rietveld analysis, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM/EDS), Ultraviolet-visible (UV-vis) spectroscopy and the Brunauer-Emmett-Teller (BET) method. The obtained results indicate the significant role of the Ag concentration and that the phase transformation changed the samples' characteristics, including an increased crystallite size and absorbance. The results also showed that the Ag/SiO2 composite with a uniform microstructure in the form of spherical Ag particles with a relatively uniform size were dominated by silver and cristobalite phases as the main phases. Meanwhile, the silver phase emerged as a dominant phase and was embedded in the silica matrix. The crystal sizes of the silver and cristobalite were found to be 40 and 20 nm, respectively. The absorbance value showed that Ag/SiO2 works on two wavelengths of 310 and 415 nm. The obtained surface area values ranged from 5.0 -11.4 m2 g-1 which belongs to the mesopore criteria. Such structural and textural properties of the produced composite indicate its suitability to be used as a catalyst.