Effect of Dimensionality on the Photocatalytic Behavior of Carbon-Titania Nanosheet Composites: Charge Transfer at Nanomaterial Interfaces.

Due to their unique optoelectronic structure and large specific surface area, carbon nanomaterials have been integrated with titania to enhance photocatalysis. In particular, recent work has shown that nanocomposite photocatalytic performance can be improved by minimizing the covalent defect density of the carbon component. Herein, carbon nanotube-titania nanosheet and graphene-titania nanosheet composites with low carbon defect densities are compared to investigate the role of carbon nanomaterial dimensionality on photocatalytic response.

Chemically homogeneous and thermally reversible oxidation of epitaxial graphene.

With its exceptional charge mobility, graphene holds great promise for applications in next-generation electronics. In an effort to tailor its properties and interfacial characteristics, the chemical functionalization of graphene is being actively pursued. The oxidation of graphene via the Hummers method is most widely used in current studies, although the chemical inhomogeneity and irreversibility of the resulting graphene oxide compromises its use in high-performance devices.

Minimizing oxidation and stable nanoscale dispersion improves the biocompatibility of graphene in the lung.

To facilitate the proposed use of graphene and its derivative graphene oxide (GO) in widespread applications, we explored strategies that improve the biocompatibility of graphene nanomaterials in the lung. In particular, solutions of aggregated graphene, Pluronic dispersed graphene, and GO were administered directly into the lungs of mice. The introduction of GO resulted in severe and persistent lung injury.

Minimizing graphene defects enhances titania nanocomposite-based photocatalytic reduction of CO2 for improved solar fuel production.

With its unique electronic and optical properties, graphene is proposed to functionalize and tailor titania photocatalysts for improved reactivity. The two major solution-based pathways for producing graphene, oxidation-reduction and solvent exfoliation, result in nanoplatelets with different defect densities. Herein, we show that nanocomposites based on the less defective solvent-exfoliated graphene exhibit a significantly larger enhancement in CO(2) photoreduction, especially under visible light.

Highly concentrated graphene solutions via polymer enhanced solvent exfoliation and iterative solvent exchange.

Efficient graphene exfoliation in a nontraditional solvent, ethanol, is achieved through the addition of a stabilizing polymer, ethyl cellulose. Iterative solvent exchange is further demonstrated as a rapid, room-temperature, ultracentrifugation-free approach to concentrate the graphene solution to a level exceeding 1 mg/mL. The outstanding processability and electrical properties of these graphene inks are verified through the realization of aligned graphene-polymer nanocomposites and transparent conductive graphene thin films.