C60-encapsulated TiO2nanoparticles for selective and ultrahigh sensitive detection of formaldehyde.

The current study concerns development of fullerene-C60-encapsulated TiO2nanoparticles hybrid for an efficient detection of volatile organic compounds (VOCs). The nanocomposite was synthesized via chemical route by using hydrated fullerene-C60and sol-gel derived undopedp-type TiO2nanoparticles. The nanocomposite was characterized morphologically and structurally comparing with pure C60clusters and pure TiO2nanoparticles as the reference materials. The average diameter of the C60-encapsulated TiO2nanoparticles was 150 nm whereas the average diameters of C60clusters and pure TiO2nanoparticles were 161 nm and 18 nm respectively. Therefore, all the materials were implemented in interdigitated electrode based planner structured sensors and tested towards multiple VOCs. However, C60-TiO2composite exhibited its natural selectivity towards formaldehyde with a very high sensitivity for the concentration range of 1-1000 ppm. C60-encapsulated TiO2nanoparticles depicted more than double response magnitude (117%) than the pure TiO2nanoparticle (48%) and pure C60particles (40%) and appreciably fast response/recovery (12 s/331 s) towards 100 ppm of formaldehyde at 150 °C. However, the efficient VOC sensing was achieved in C60-encapsulated TiO2sensors possibly due to the extreme reactive surface provided by the oxygen functionalized C60and easy electronic exchange between ambient and the TiO2nanoparticles through C60layers. The combined properties of both C60and TiO2lead to the formation of a promising nanocomposite which provided better sensing characteristics than that of the pure materials.