ELECTROCHEMICAL PROPERTIES OF CARBON DOTS AND THEIR USE AS PHOTOCATALYSTS IN C−O BOND FRAGMENTATION

Abstract

Photocatalysis is emerging as a powerful synthetic tool that aims to use solar light to promote organic transformations by mimicking what plants do with photosynthesis. Over the last century, huge efforts have been made by researchers to discover photocatalysts that can be effectively triggered under the irradiation of suitable wavelengths. Among these, very recently carbon dots (CDs) have shown to be promising luminescent bio-based nanomaterials that can be used as sustainable and economical alternatives to the classical metal-based photocatalysts. These nanoparticles have been used in many different applications as nano-optoelectronic devices, sensors and nano-carriers. However, CDs have so far been generally under-explored in photochemical applications and predominantly in conjunction with other photosensitizers, semiconductors and metallic redox mediators for the production of hydrogen, and for the conversion of carbon dioxide into small organic molecules. In this thesis we describe the complete electrochemical characterization of a library of CDs by cyclic voltammetry and we test their efficiency in the photo-reductive cleavage of C-O bonds, by using picolinium esters as model substrates, without using any redox mediators. The surprising efficacy, ease of synthesis and the fact that these CDs can be made from renewable sources make these nanomaterials good candidates for new metal-free and light-enhanced organic synthetic protocols.