In Situ One-Pot Synthesis of 1-Dimensional Transition Metal Oxide Nanocrystals

One-dimensional colloidal metal oxide nanocrystals are of great importance in materials chemistry, but reports on these materials are rare due to lack of well-defined synthetic protocols. In this paper, we present a general and highly effective one-pot synthetic protocol to produce 1-dimensional nanostructures of transition metal oxide (e.g., W18O49, TiO2, Mn3O4, and V2O5) through thermally induced crystal growth processes from a mixture of metal chloride and surfactants

Transformative Two-Dimensional Layered Nanocrystals

Regioselective chemical reactions and structural transformations of two-dimensional (2D) layered transition-metal chalcogenide (TMC) nanocrystals are described. Upon exposure of 2D TiS2 nanodiscs to a chemical stimulus, such as Cu ion, selective chemical reaction begins to occur at the peripheral edges. This edge reaction is followed by ion diffusion, which is facilitated by interlayer nanochannels and leads to the formation of a heteroepitaxial TiS2–Cu2S intermediate. These processes eventually result in the generation of a single-crystalline, double-convex toroidal Cu2S nanostructure. Such 2D regioselective chemical reactions also take place when other ionic reactants are used. The observations made and chemical principles uncovered in this effort indicate that a general approach exists for building various toroidal nanocrystals of substances such as Ag2S, MnS, and CdS

Ultrathin Zirconium Disulfide Nanodiscs

We present a colloidal route for the synthesis of ultrathin ZrS2 (UT-ZrS2) nanodiscs that are ∼1.6 nm thick and consist of approximately two unit cells of S–Zr–S. The lateral size of the discs can be tuned to 20, 35, or 60 nm while their thickness is kept constant. Under the appropriate conditions, these individual discs can self-assemble into face-to-face-stacked structures containing multiple discs. Because the S–Zr–S layers within individual discs are held together by weak van der Waals interactions, each UT-ZrS2 disc provides spaces that can serve as host sites for intercalation. When we tested UT-ZrS2 discs as anodic materials for Li+ intercalation, they showed excellent nanoscale size effects, enhancing the discharge capacity by 230% and greatly improving the stability in comparison with bulk ZrS2. The nanoscale size effect was especially prominent for their performance in fast charging/discharging cycles, where an 88% average recovery of reversible capacity was observed for UT-ZrS2 discs with a lateral diameter of 20 nm. The nanoscale thickness and lateral size of UT-ZrS2 discs are critical for fast and reliable intercalation cycling because those dimensions both increase the surface area and provide open edges that enhance the diffusion kinetics for guest molecules