Identificador: TDX:3099
Autors: Casanova Cháfer, Juan
Resum:
This thesis focuses in the development of different gas sensors through the modification of carbon nanomaterials. In particular, we employed carbon nanotubes (CNT), graphene and diamondoids, with different approaches. For instance, these nanomaterials were either decorated with metal oxide nanoparticles, modified of self-assembled monolayers of thiols or functionalized with different molecules or atoms, among other strategies. Despite the outstanding properties of carbon nanomaterials, such as their electronic, physicochemical and mechanical properties, it has not been possible so far to develop commercial sensors based on these nanomaterials. The main reason is derived from their inherent problems in the gas molecule detection process, such as low specificity and limited reactivity. Thus, we developed new gas sensors by modifying carbon nanomaterials to improve essential gas sensing parameters, such as selectivity, sensitivity and response time. Furthermore, an exhaustive material characterization was carried out through spectroscopic and microscopic techniques. Also, detailed gas sensing mechanisms were proposed, ergo, the physicochemical interactions between nanomaterials and gases were studied. In consequence, this thesis provides a comprehensive vision for the development of new gas sensors employing carbon nanomaterials, from their design and characterization to their working principles at to the atomic scale. In consideration of the social concerns, the sensors developed usually work at room temperature. Therefore, the device power-consumption was drastically reduced. In summary, the modified carbon nanomaterials employed in this thesis can detect harmful gases, such as nitrogen dioxide, at trace concentration, even at lower levels than those established by law as threshold limit values.
Repositori URV