Textural and morphological studies of transition metal doped SBA-15 by co-condensation method

Abstract

The 3d transition metals were incorporated into SBA-15 matrix by co-condensation synthesis method. Very low concentrations of metals were introduced into silica framework by maintaining the metal to silica ratio in the synthesis gel at 0.01. The difference in hydrolysis rates of metal and silica precursors have led to textural modifications while demonstrating the structural integrity akin to pristine SBA-15. The physicochemical properties obtained offer some insights into the P123 micelle aggregation and mechanism of formation of silica network in the presence of metal salts under similar synthesis conditions of pure SBA-15. The metal doping into SBA-15 leads to increased pore diameters. Higher lattice constants (a0) observed in these samples are attributed to the increased pore wall thickness. The significant retention of the hexagonal mesostructure seen in LXRD indicates diminutive influence of metal salts at lower concentrations. Macroscopic morphologies studied by SEM show the formation of spheres along with conventional fibre-like rods. The 3d-transition metals were incorporated in SBA-15 by co-condensation method. The structural and textural properties of modified SBA-15 materials elucidate the increased pore wall thickness besides retaining their typical two dimensional hexagonal mesochannels with p6mm symmetry. The metal dopants have promoted the condensation of silica and induced morphological changes.