Scalable synthesis of high-purity TiO₂ whiskers via ion exchange method enables versatile applications

In this work, high-purity titanium dioxide (TiO₂) whiskers with different crystal forms were synthesized via ion exchange and controlled calcination methods. TiO₂ whiskers are of 5-10 μm in length with a length-to-diameter ratio of 10-20. A systematic investigation was established to explore the hydration process of K⁺/H⁺ exchange, anatase-rutile transformation in the calcination process and the applications of TiO₂ whiskers. Compared with the other strategies previously used for the synthesis of TiO₂ whiskers, it was found that large-scale production was obtained under mild reaction conditions, which represented a facile and mild route for industrial production and expanded the versatile applications of TiO₂ whiskers. Moreover, with the addition of nano TiO₂ colloid as a special accelerant, the calcination process yielding uniform morphology and controllable crystal form was explored. Confirmatory experiments indicated that anatase and rutile TiO₂ whiskers respectively show excellent photocatalytic activities and unique carrier performance for fabricating functional whiskers.