Optimization of the conditions in the molten salt hydrate assisted synthesis method of TiO2

Chenfeng Huang
2020
With the current transition in energy usage and concern for the environment, a primary goal is to find renewable and environmentally friendly catalysts with high activity and efficacy. To achieve this, advanced catalytic properties, such as high surface area, high acidity and low band gap energy, are of the utmost importance for heterogeneous catalysts. TiO2 is one promising metal dioxides with good mechanical structure, prevalent in both Lewis and Bronsted acid sites, low band gap energy,
more » ... nd gap energy, non-toxicity and cost effectiveness. Synthesis of TiO2 is itself not particularly novel. Sol-gel, hydrothermal, physical vapor deposition, and microwave methods have been widely studied for the production of titania. However, synthesis of TiO2 via molten salt hydrates (MSHs) have limited exposure in the open literature. In MSH, ion-water interaction is optimized and water-water interactions are minimized; by changing ratios of water/salt and salt/precursor, modification of the structure, morphology and chemical properties of synthesized materials can be achieved. Therefore, the project was undertaken in order to understand how the MSH system affects crystalline growth and to synthesize TiO2 with desirable catalytic properties. In this work, Titanium Isopropoxide (TTIP) was utilized as the precursor, using a MSH-assisted sol-gel method to synthesize TiO2 with varying properties by changing the ratio of water/LiBr and LiBr/TTIP. In order to understand the effect of the MSH system, XRD, N2-BET, Raman, SEM, UV-vis and TPD-MS techniques were applied to characterize these samples. Likewise, TiO2 phase transformation was observed to investigate thermal stability. Samples were calcined at different temperatures ranging from 400 to 600°C to observe phase transformation in TiO2 using Raman; XRD was further used to quantify preponderance of anatase, brookite and rutile phases and to identify phase transition. Since TiO2 serves as a semiconductor and photocatalyst, electronic spectroscopy was taken for all samples to measure the band gap e [...]
doi:10.7282/t3-knyr-9873 fatcat:psxuxqrjujfpjmzhokftcrkpnq