Experimental variables in the synthesis of brookite phase TiO2 nanoparticles

Nanocrystalline brookite titanium dioxide particles have been prepared under ambient condition sol process. Titanium tetrachloride was the precursor in water with isopropanol as the co-solvent in hydrochloric acid. The formed gel mass was peptized and crystallized under refluxing condition. The effect of various parameters, such as temperature, time, water to alcohol ratio, and pH of the sol on the phase obtained were investigated. The refluxing temperature of 83 °C with the refluxing time of 15 h led to the formation of pure brookite phase as indicated by X-ray diffractometry (XRD). Whereas, lower temperature of 70 °C gave a mixture of rutile and anatase phases, and higher temperature of 100 °C gave mixture of rutile and brookite phases. Addition of hydroxypropyl cellulose yielded a more uniform particle size along with higher surface area. The water to alcohol ratio had minimal effect, when taken in the ratio of 1:2 or above, on the brookite phase formation.