DEVELOPMENT OF PHOTOCATALYST MATERIALS BASED ON TITANIA DECORATED MESOPOROUS SILICA WITH BICONTINUOUS CONCENTRIC LAMELLAR (BCL) MORPHOLOGY

• Main Author: Adiwijaya, Steven
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/68069
• Institution: Institut Teknologi Bandung

Mesoporous silica is an oxide compound that has a pore size of 2.0 to 50 nm. In its development, mesoporous silica material has become one of the materials with wide applications because it has adjustable particle size, porosity, and morphology. Some of the main applications of mesoporous silica material are as sensors, adsorbents, catalyst supports, gas storage, drug fillers, and chromatographic stationary phases in the separation process. One of the interesting silica morphology is the bicontinuous concentric lamellar (bcl). The advantages of bcl morphology are that it has a large surface area and pore volume, a pore with an open channel structure in the form of a v-groove, as well as spherical particles with a fairly large size. The unreactive and insulating nature of silica makes bcl silica unsuitable as a catalyst or photocatalyst. Although silica does not have catalytic properties, the properties of silica which have good chemical, mechanical and thermal resistance, as well as transparency make bcl silica the right choice as a photocatalyst buffer, such as TiO2. So in this research, the impregnation of TiO2 photocatalyst material to the silica bcl surface will be carried out. The formation of silica bcl particles decorated with TiO2 is divided into 2 stages, namely the formation of silica bcl, which is then followed by decoration of TiO2. Bcl silica is generally synthesized solvothermally using a Teflon-lined autoclave at high pressure. Meanwhile, in this study, silica bcl was synthesized by reflux method at atmospheric pressure which is easier to increase in large-scale production. TiO2 photocatalyst is synthesized from ethanol stabilized TiCl4 precursor which is easier to handle and more economical. Based on the FE-SEM images, titania-decorated bcl silica was successfully synthesised by a simple dripping method. On EDS mapping, the percent of titania atoms decorating the surface of bcl silica samples for each treatment was obtained. EDS mapping shows that the sample with calcined silica bcl has a titania atomic composition of 7.3%, while the sample with uncalcined silica has a titania atomic composition of 6.2%. Stabilised TiCl4 precursor can be formed consistently in 10% ethanol at 0°C. Raman data showed that titania successfully decorated onto the silica surface is a mixture of anatase phase and rutile phase. UV-vis data showed a pattern of decreasing band gap energy of the sample as the number of titania particles in the sample increased. For calcined bcl silica, the band gap decrease occurs from 3.25 eV in the sample which labelled as 0,5, down to 3.06 eV in the sample which labelled as 3. Meanwhile, the pre-calcined bcl silica decreased from 3.25 eV in the sample which labelled as 0,5, down to 3.17 eV in the sample which labelled as 3. Photodegredation experiment data shows that the lamp used is not effective in forming excitons on the photocatalyst sample. The inhibition of exciton formation is due to the tangent area between the peak of the lamp beam and the sample absorption area is relatively small. Based on the results of photocatalytic activity testing, silica with retained silanol activity has better photocatalytic properties than silica with deactivated (calcined) silanol. Photocatalytic activity testing showed that the photocatalyst using uncalcined silica buffer with TiCl4 dripping concentration of 4.3248 M / precursor TiCl4 labelled as 3 produced the best photodegredation reaction rate.