Vasileios Tzitzios

Facile MoS2 growth on reduced graphene-oxide via liquid phase method

Single and few-layers MoS2 were uniformly grown on the surface of chemically reduced graphene oxide (r-GO) via a facile liquid phase approach. The method is based on a simple functionalization of r-GO with oleyl amine which seem to affect significantly the MoS2 way of growth. Scanning transmission electron microscopy (STEM) and Atomic Force Microscopy (AFM) analysis reveal the presence of single-layer MoS2 on the surface of a few-layers r-GO. XPS and Raman spectroscopies were used for in-depth structural characterization. Furthermore, we have successfully applied the method to synthesize MoS2 nanocomposites with multiwall carbon nanotubes (CN) and carbon nanofibers (CNF). The results demonstrate clearly the selective MoS2 growth on both carbon-based supports.

Direct liquid phase synthesis of ordered L10 FePt colloidal particles with high coercivity using an Au nanoparticle seeding approach

Ordered L10 and high coercivity FePt nanoparticles were successfully synthesized via a chemical method using pre-synthesized Au nanoparticles as nuclei seeds. The size of the Au nanoparticles seems to play a significant role in the formation of the tetragonal phase (L10) FePt colloidal nanoalloys. Seeding with ∼12 nm diameter monodispersed Au nanoparticles in the reaction mixture was found to lead to partial L10 FePt particles with 2.8 kOe coercivity at room temperature, while seeding with ∼6 nm Au nanoparticles leads to the formation of well L10 ordered FePt colloidal particles with 8.8 kOe coercivity at room temperature, one of the highest values for the direct liquid phase synthesis of L10 FePt colloidal particles. Furthermore, seeding with smaller Au particles decreases the ordering temperature from 360 °C to 300 °C leading to the formation of more uniform well-shaped nanoparticles.