Graphitic Carbon-Based Nanostructures for Energy and Environmental Application

This thesis focuses on the synthesis and characterization of graphitic carbonbased photocatalytic nanostructures for energy and environmental applications. The preparation of carbon- and oxygen-rich graphitic carbon nitride with enhanced photocatalytic hydrogen evolution property was investigated. Composite materials based on graphene quantum dots were also prepared. These composites were used for photocatalytic degradation of organic pollutants and photoelectrocatalytic disinfection.;The first part of this thesis describes a facile method for the preparation of carbon- and oxygen-rich graphitic carbon nitride by thermal condensation. Incorporation of carbon and oxygen enhanced the photoresponse of carbon nitride in the visible-light region. After exfoliation, the product was c.a. 45 times more active than bulk graphitic carbon nitride in photocatalytic hydrogen evolution under visible-light irradiation.;In the second part, a simple approach to enhance the photocatalytic activity of red phosphorus was developed. Mechanical ball milling was applied to reduce the size of red phosphorus and to deposit graphene quantum dots (GQDs) onto red phosphorus. The product exhibited high visible-light-driven photocatalytic performance in the photodegradation of Rhodamine B.;The incorporation of GQDs in titanium dioxide could also extend the absorption spectrum of TiO2 into the visible-light range. The third part of this thesis reports on the fabrication of a visible-light-driven composite photocatalyst of TiO2 nanotube arrays (TNAs) and GQDs. Carboxyl-containing GQDs were covalently coupled to amine-modified TNAs. The product exhibited enhanced photocurrent and high photoelectrocatalytic performance in the inactivation of E. coli under visible-light irradiation. The role of various reactive species in the photoelectrocatalytic process was investigated.