Multiphase TiO₂ aerogels were synthesized through a simple, environment friendly sol–gel route. TiCl₃ was used as nonalkoxide precursor with ethanol as solvent. The formed alcogels were converted into aerogels by CO₂ supercritical drying. The results revealed that the increase in TiCl₃ concentration leads to the decay of the gelation time, possibly due to the availability of Ti⁺⁴ ions in the medium that led to the formation of the interconnected gel network more easily. The aerogels produced from 0.75 M TiCl₃ and calcined at 450 °C exhibited the three main crystalline phases of titania (anatase, brookite, and rutile) and a specific surface area of 124 m²/g. Through transmission electron microscopy, it was possible to visualize the morphology of the nanostructured aerogels, comprised of a network of nanoparticles with sizes between 5 and 15 nm. The combination of high specific surface area, particle size in nanometer scale, and crystallinity of the material allowed greater photocatalytic reduction of 4-nitrophenol compared with commercial Degussa P-25.

多相TiO ₂气凝胶是通过简单，环境友好的溶胶-凝胶路线合成的。TiCl ₃用作非醇盐前体，乙醇为溶剂。通过CO ₂超临界干燥将形成的醇凝胶转化为气凝胶。结果表明，TiCl ₃浓度的增加导致胶凝时间的下降，这可能是由于介质中Ti ⁺⁴离子的可用性，从而更容易形成相互连接的凝胶网络。由0.75 M TiCl _3产生并在450°C下煅烧的气凝胶表现出三氧化钛的三个主要结晶相（锐钛矿，板钛矿和金红石），比表面积为124 m ²/G。通过透射电子显微镜，可以可视化纳米结构气凝胶的形态，该结构由大小在5到15 nm之间的纳米颗粒网络组成。与商业Degussa P-25相比，高比表面积，纳米级粒径和材料的结晶性相结合，可以使4-硝基苯酚具有更大的光催化还原能力。