QUANDO L'INSIEME È MEGLIO DELLA SOMMA: NANOMATERIALI IBRIDI ARGENTO-TITANIA ED ORO-TITANIA PER SENSORI ELETTROANALITICI

Abstract

The interest of the scientific community for nanotechnologies and nanomaterials was born in 1959, on the occasion of the annual meeting of the American Physical Society, when a new approach began with which to consider and manipulate matter on a micro- and nano-metric scale. The subsequent increase in the use of nanomaterials in scientific research is due to their peculiar characteristics: increased surface / volume ratio, new optical and physical properties, high active surface, increased or modified material transport, increased selectivity. All these features make nanomaterials extremely suitable for a wide range of applications, from energy, to catalysis and sensors. In recent decades, apart from the application of nanomaterials characterized by a single component, the use of “hybrid” nanomaterials, composed of two or more components in “intimate” contact, is also rapidly growing. This is connected to the fact that, since in a hybrid material the establishment of synergistic properties is confined to the contact region between the different components, in nanomaterials, given the small size, these effects can become a dominant factor of the entire structure. The result is precisely the establishment of new and unexpected properties (often desired and interesting) which are not the simple sum of the ownership of individual contributions. Given all this, hybrid materials are excellent candidates for applications in the most varied fields, including electroanalysis, which can greatly benefit from these systems. In this context, this work aims to present the construction of devices based on hybrid metal-semiconductor nanomaterials (based on silver or gold nanoparticles and titanium dioxide). In these systems, the presence of metal nanoparticles is exploited for the electroanalytical determination of analytes of medical / diagnostic or environmental interest, while the presence of TiO2 is essential for overcoming the problems of fouling and passivation of the electrode surface following the determination of the molecule under examination. . The possibility of renewing the electrode surface simply by irradiating the device with ultraviolet light, allows you to use the devices remotely for a long time, without their continuous recovery. In the case of the Ag-TiO2 system, an “intimate contact” interphase between the silver nanoparticles and titanium dioxide was also found, which makes the hybrid a real new material, with different characteristics and with interesting applications compared to its precursors.