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

Abstract

Composites of silver-doped rice husk silica using sol-gel method has been conducted. Silver nitrate and rice husks were used as resources. Composites were sintered at 850°C and then characterized using Infrared Spectrophotometer (FTIR), x-ray diffractometer (XRD) coupled with Rietveld analysis, Electron Microscope (SEM/EDS), Ultraviolet-visible (UV-vis) spectroscopy and The Brunauer-Emmett-Teller (BET) methods. Results obtained indicate significant role of Ag concentration and that phase transformation changed samples characteristics, including increased crystallite size and absorbance. Results also showed that Ag/SiO₂ composite with uniform microstructure in the form of spherical particles of Ag with relatively uniform size which were dominated by silver and cristobalite phases as the main phases. Meanwhile, silver phase emerged as a dominant phase and was embedded in a silica matrix. The crystal sizes of silver and cristobalite were found to be 40 and 20 nm, respectively. Absorbance value showed that Ag/SiO₂ work on two wavelengths of 310 and 415 nm. Surface area values obtained range from 5.0-11.4 m²/g that belongs to the mesopores criteria. Such structural and textural properties of the produced composite indicate its suitability to be used as catalyst.

Keywords

• keywords: silica
• silver
• sol-gel
• ag-sio₂ composites