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 (a 0 ) 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.

Impact of heteroatom addition into mesoporous silica for water adsorption in the low partial pressure range

“…An important characteristic presented by this group were that the values of micropore surface area and volume displayed average increases of 146% and 119%, respectively, when compared to pure silica. Charan and Rao [ 39 ] also reported that the insertion of heteroatoms by co-condensation may alter the amount of micropores in SBA-15 samples. This would occur because the presence of the metals changes the energy of the surfactant-solution interface, since the metals compete with silica in the S 0 H + X − I + mechanism (S 0 H + being the surfactant hydrogen bonded to a hydronium ion, X − the chloride ion and I + the protonated inorganic species) [ 42 ].…”

“…The investigation regarding the isomorphic substitution of heteroatoms into the framework of silica continued through FTIR analyses. The objective was to observe if there were disturbances in the network of silica caused by the presence of foreign atoms by tracking the Si–O–Si bonds around 1060 cm −1 [ 39 , 48 , 49 ]. The maxima of the peaks associated to these bonds in functionalized samples experienced deviations around the value observed for PSi, which are shown in Fig.…”

Preparation, Characterization and Catalytic Activity of CrSBA-15 for 2-Propanol Decomposition

“…With an increasing Cr content, the intensity of the (1 0 0) peak decreases as a result of a partial blocking of the SBA-15 mesopores and the deterioration of the ordered pore structure [32]. All the materials exhibit significant changes from the d-spacing of the (1 0 0) plane to lower values in relation to the SBA-15 material, implying dilation in the framework lattice [37]. It is important to take into consideration that there is a decrease in the unit cell constant (a 0 ) and the wall thickness (e) in these materials (Table 1).…”

A Systematic Literature Review on Waste-to-Resource Potential of Palm Oil Clinker for Sustainable Engineering and Environmental Applications

“…The appearance of mesostructure characteristics, as attested by low-angle XRD, N 2 adsorption–desorption isotherms, and transmission electron microscopy (TEM), demonstrated the successful synthesis of SBA-15 using a silica originator extracted from POFA. According to the current literature, used for comparative purposes, SBA-15 synthesized from tetraethyl ortho silicate (TEOS) had the largest surface area (699 m 2 /g) [ 86 ], trailed by sodium silicate SBA catalyst with 332 m 2 /g [ 87 ] and POFA-rich silicate with 330 m 2 /g. It was noted that the surface area of the SBA-15 synthesized using POFA sodium silicate was similar to that of commercial sodium silicate.…”