A titania nanofibrous smart scaffold for elemental mercury vapour sensors - Presentazione orale in ELECTROSPIN 2016 (31June-2 July 2016, Otranto LE)

The need for fast detection systems, at low cost and low maintenance, as well as ease of use are becoming ever more urgent, sensors and sensing systems looked the most promising alternative to the traditional instruments. ? Thus, gold nanoparticles have been grown on nanofibrous scaffolds of TiO2 by photocatalysis. ? Electrospinning technology has been used successfully to create a 3D-framework of titania covering the electrode sensing area of the properly designed chemoresistors (IDEs). ? By dipping the samples within tetrachloroauric solutions under UV irradiation, the titania layers proceeded the nucleation of gold nanospheres lonely on the fibres. ? Small changes of HAuCl4 concentration allowed to tune both size, arrangement and distribution of the AUNPs along the fibres. ? Small changes of the precursor solution of titania (TRITON X) can affect roughness and nanogold growth and distribution. ? The sensor is expected to be robust since it is composed with titania and gold, two chemical compounds considered among the most robust materials since resistant to common solvents and VOCs as well as microorganisms attacks. ? Additionally, the sensor has been designed to work at room temperature being thermally treated (450°C) only for a few minutes up to desorb mercury from AuNPs, thus thermal drift effects are expected to be lowered. ? The nanofibrous layers loaded with more particles resulted conductive at room temperature (Ohmic behaviour) and suitable to change their current values to low concentrations of mercury vapours (tens of ppt). ? The fabricated nanostructured chemosensors worked as Hg0 vapours highly adsorbing 3D-conductive traps, capable of working until the saturation of all the interacting sites occurred. ? Depending on the strategy of sampling, the limit of detection could be improved, about 6 ppt when mercury vapour was injected and about 2 ppt when slowly flowed within the measuring chamber.