Applications of Mesoporous Ordered Semiconductor Materials — Case Study of TiO2

TiO2 is a promising material for technological applications for its versatility [1-4], abundance, low toxicity, good chemical stability, photosensitivity and photostability [5-8]. In nature, it is found mainly in the mineral ilmenite [9], that can be processed industrially by two different routes [10]: The first, involves the reaction of the concentrate of ilmenite with hot sulphuric acid, resulting in the formation of sulphates of titanium, Fe(II) and Fe(III), being these last eliminat‐ ed by centrifugation, after cooling. The final solution is then purified and hydrolyzed to produce pure TiO2 [11]. The other usual way of obtaining consists in combining the ore with coke and gaseous chlorine under heating, resulting in CO2 and a spongy material rich in TiCl4. The reaction product is subjected to successive fractional distillation, with the formation of TiCl2 and TiCl3, due to stability of titanium in other degrees of oxidation. The different precursors of titanium are hydrolyzed, forming titanium dioxide [12].