Effect of metal dopant in silica sol-gel reaction

Loading...
Thumbnail Image
Date
2019-06
Authors
Aziatul Atika Binti Roslan
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Silica membrane becomes one of the important ceramic product due to its properties that suitable in gas separation processes. The sol-gel method is used to synthesis the microporous silica material due to its simplicity and the high degree of nanoscale homogeneity which vital for good separation. Therefore, the aim of this study is to investigate the effect of metal dopant on the silica structure via sol-gel method. In this study, the silica xerogel (powder) is prepared via the sol-gel method instead of the silica membrane as it is easier to optimise material characteristic in material form. There are various types of metals being doped into the silica solution to investigate their effect on silica structure such as Nickel (II) Chloride Hexahydrate (NiCl2.6H2O), Cobalt (II) Chloride Hexahydrate (CoCl2.6H2O), Copper (II) Chloride dihydrate (CuCl2.2H2O). However, only the effect of nickel is further studied at different molar ratio of Ni/Si (0.02, 0.03, 0.04 and 0.05) and calcination temperature (430°C, 530°C, 630°C and 730°C). Besides, different ratio of alkoxide/water, Rw is studied to investigate the effect of Rw on silica structure. The UV-Vis spectrophotometer and FTIR spectra are used to analyse the effect on silica structure. The result shows that Si-O-Me formed in metal-doped silica structure lead to lower formation of siloxane bond. This results in small pore size of metal-doped silica structure compared to pure silica structure. Next, the higher the concentration of NiCl2.6H2O, the smaller the pore size of silica due to the higher formation of Si-O-Ni bond. Besides, silica structure is less hydro-stable at lower the alkoxide/water ratio, Rw due to the higher formation of silanol which leads to the lower formation of siloxane bond. Lastly, the optimum calcination temperature to synthesis silica nanoparticle is 630°C
Description
Keywords
Citation