RICE HUSK ASH SILICA AS A SUPPORT MATERIAL FOR RUTHENIUM BASED HETEROGENOUS CATALYST

Heterogeneous ruthenium catalysts supported on silica from rice husk ash (RHA-Ru) was prepared by precipitation using an aqueous solution of metal salt in 3.0 M HNO3. The effect of calcination at high temperature upon the surface and bulk structure of the catalyst precursor has been investigated. X-ray diffraction studies on RHA-Ru showed that it existed in an amorphous state. However, on calcination at 700ºC, RHA-Ru700 showed some degree of crystallization. The Scanning Electron Microscopy (SEM) micrographs showed the formation of well-defined flat elongated nano-sized rods with a smooth outer surface among the amorphous powder. RHA-Ru had a specific surface area of ca. 65 m2 g–1, while RHA-Ru700 had only ca. 10 m2 g–1, which is consistent with the formation of rod shaped crystalline phase. Both samples had pores in the mesoporous range. The Fourier transform infrared (FTIR) spectrum showed the presence of groups in RHA-Ru which was not present in RHA-Ru700. The Brunner Emmet Teller (BET) isotherm showed both samples had H3 hysteresis. Energy Dispersive Spectrometry (EDX) analysis showed that the distribution of Ru in the silica matrix was not homogeneous in RHA-Ru, however, it was found to be more homogeneous in RHA-Ru700.