Enhancing the optical transparency of TiO2 aerogels with high surface area through water-based synthesis

Abstract

Abstract In this work, we report a one-step, green synthesis of highly transparent TiO2 aerogels with high specific surface area through a sol-gel method. For gel synthesis, water was used as solvent and TiCl3 as precursor. After CO2 supercritical drying of the gels, aerogels with specific surface area as high as 735 m2/g were obtained. The results were compared to a known ethanolic route for TiO2 aerogels starting from Titanium (IV) isopropoxide as precursor. After calcination at 450 °C only anatase phase was detected in the samples produced both in ethanolic or in aqueous medium. The aqueous TiO2 aerogels comprise smaller particle sizes of 2.2 nm in average and homogeneous pore structure, which resulted in aerogels with very high transparency in the visible region. This new proposed route yielded TiO2 aerogels with remarkable properties that can be used in a wide range of optoelectronic applications including photovoltaics, photocatalysis and optical sensing.