Pigmentary properties of rutile TiO2 modified with cerium, phosphorus, potassium, and aluminium

The influence of different modifiers, phosphorus, potassium, aluminium, and cerium on the pigmentary properties of TiO₂ was studied. The phase composition and distribution of modifiers in prepared TiO₂ products was investigated using XRD analysis, the selective leaching method, and ICP-AES technique. The optical properties, photoactivity, morphology, and surface area of modified TiO₂ were determined by spectrophotometric, fluorescent, SEM, and BET measurements. The research was directed towards obtaining a pigmentary TiO₂ with the highest possible photostability. It was found that the final calcination temperature, at which the anatase-rutile transformation rate was > 97 %, depended on the kind and amount of the modifiers introduced into hydrated titanium dioxide. In comparing the colour of TiO₂ products modified with Ce, it was found that the addition of K to the TiO₂ series caused an increase in all the optical properties examined. The presence of K and Al in TiO₂ modified with Ce resulted in decreased photocatalytic activity. The photostability of TiO₂ modified with Ce and K improved with an increase in P₂O₅ content. The highest photostability was measured for the TiO₂-CePKAl series. It was concluded that the differences in both the optical properties and photoactivity of TiO₂ depended on its phase composition and the distribution of modifiers in the products obtained.