Preparation of Unique TiO2 Nano-particle Photocatalysts by a Multi-gelation Method for Control of the Physicochemical Parameters and Reactivity

Abstract

A novel multi-gelation method to prepare TiO 2 nano-particle photocatalysts showed good performance in controlling the important parameters determining the photocatalytic reactivity, i.e., the particle size, surface area, crystallinity, pore-volume, porediameter as well as the anatase and rutile phase composition of the catalysts. In particular, this method at higher pH swing times could prevent the phase transition from anatase to rutile, leading to higher photocatalytic activity. By adopting variations in the pH swing, the TiO 2 nano-particle photocatalysts showed significantly higher photocatalytic reactivity for the complete oxidation of 2-propanol diluted with water into CO 2 and H 2 O. It can be considered a viable alternative method for the preparation of high performance TiO 2 nano-particle photocatalysts for widespread commercial applications KEY WORDS: TiO 2 photocatalysts; multi-gelation method; photocatalytic degradation of 2-propanol.

Ultrasonic-assisted pH Swing Method for the Synthesis of Highly Efficient TiO2 Nano-size Photocatalysts

“…Our previous findings using the pH swing method also yielded TiO 2 samples with high surface area, pore size and pore volume [6]. In the earlier method, we alternated the addition of TiCl 4 (as an acid solution) and aqueous ammonia (as a basic solution) to water at regular intervals without adjusting the pH of the reaction mixture [6].…”

“…Especially, in studies of environmental and electronic applications, TiO 2 nanoparticles show tremendous changes in activity. They are widely used in environmental cleaning processes as photocatalysts, in the fabrication of solar-fuel cells, light emitting diodes, and other useful applications [1][2][3][4][5][6][7][8][9][10]. In addition to environmental remediation processes, much attention has been focused on mesoporous TiO 2 for solar cells and fuel cells since TiO 2 nanoparticles are highly efficient materials [2][3][4][5].…”

Preparation of TiO2 nano-particle photocatalysts by a multi-gelation method: the effect of pH change

“…• C and 30 pH swings [14], whereupon the anatase phase of TiO 2 changed to the rutile phase. When the catalysts were subjected to calcination above 600…”

“…• C, whereas with the flexible pH method (pH Fle) the anatase phase gradually increased with an increase in the number of pH swings [14]. For example, at 5 pH swings 3% anatase phase was formed for the pH Fle method calcined at 650…”

“…The pH swing method enables the control of the intrinsic, as well as extrinsic properties of the TiO 2 photocatalysts by a simple change in the pH of the reaction mixture during preparation [14]. An earlier pH swing method followed the principle of alternating the addition of TiCl 4 (as an acid solution) and aqueous ammonia (as a basic solution) to water at regular intervals without adjusting the pH of the reaction mixture [14]. In the present study, the pH of the solution was kept constant at around 2 using HCl acid and at 8 using aqueous ammonia during preparation.…”