Design of Metal@Titanium Oxide Nano-heterodimers by Laser-Driven Photodeposition: Growth Mechanism and Modeling.

In order to circumvent the usual nucleation of randomly distributed tiny metallic dots photodeposited on TiO nanoparticles (NPs) induced by conventional UV lamps, we propose to synthesize well-controlled nanoheterodimers (NHDs) using lasers focused inside microfluidic reactors to strongly photoactivate redox reactions of active ions flowing along with nanoparticles in water solution. Since the flux of photons issued from a focused laser may be orders of magnitude higher than that reachable with classical lamps, the production of electron-hole pairs is tremendously increased, ensuring a large availability of carriers for the deposition and favoring the growth of a single metallic dot as compared to secondary nucleation events. We show that the growth of single silver or gold nanodots can be controlled by varying the beam intensity, the concentration of the metallic salt, and the flow velocity inside the microreactor.

Versatile template-directed synthesis of gold nanocages with a predefined number of windows.

Highly symmetrical gold nanocages can be produced with a controllable number of circular windows of either 2, 3, 4, 6 or 12 via an original fabrication route. The synthetic pathway includes three main stages: the synthesis of silica/polystyrene multipod templates, the regioselective seeded growth of a gold shell on the unmasked part of the silica surface and the development of gold nanocages by dissolving/etching the templates. Electron microscopy and tomography provide evidence of the symmetrical features of the as-obtained nanostructures.

Colloidal molecules and patchy particles: complementary concepts, synthesis and self-assembly.

This review describes the latest advances in the synthesis and assembly of specific colloids such as the colloidal molecules as defined by van Blaaderen in 2003 and the patchy particles imagined a few years later. The two concepts are closely related because some may serve as precursors of others and vice versa. To best mimic the molecular structures, it is necessary to introduce the notions of directed binding and valence which result in the concept of patches arranged on the particle surface according to the conventional repulsion figures.

Controlling the {111}/{110} Surface Ratio of Cuboidal Ceria Nanoparticles.

The ability to control the size and morphology is crucial in optimizing nanoceria catalytic activity as this is governed by the atomistic arrangement of species and structural features at the surfaces. Here, we show that cuboidal cerium oxide nanoparticles can be obtained via microwave-assisted hydrothermal synthesis in highly alkaline media. High-resolution transmission electron microscopy (HRTEM) revealed that the cube edges were truncated by CeO{110} surfaces and the cube corners were truncated by CeO{111} surfaces.

Effect of solvent on silicon nanoparticle formation and size: a mechanistic study.

Silicon has emerged as the most desirable material for optical dielectric metamaterials, however chemists struggle to obtain the required silicon nanoparticle dimensions. Here the average diameter of silicon nanoparticles is varied between 3 and 15 nm by changing the reaction solvent. Electrochemistry and NMR elucidate the role of solvent on the synthetic mechanism.