Spontaneous Hierarchical Assembly of Rhodium Nanoparticles into Spherical Aggregates and Superlattices

Abstract

Reduction of aqueous RhCl 3 with NaBH 4 in the presence of poly(vinyl pyrrolidone) (PVP) yields dense spherical nanostructures. The spherical aggregates, which generally have diameters between 10 and 100 nm, are built from smaller 1-3 nm Rh particles. The dense nanostructures are thermally stable beyond 100 °C, and they have a tendency to form ordered superstructures upon drying. Combining sodium n-dodecyl sulfate (SDS) with PVP modifies the size and morphology of the primary 1-3 nm particles, but does not change the spherical shape of the aggregates except at high concentrations of SDS. Smallangle X-ray scattering measurements show that the large aggregates are formed directly in solution from small Rh particles, consistent with TEM and AFM results. Magnetic measurements indicate that the Rh nanoparticle aggregates are Pauli paramagnetic.

Nucleation and growth mechanisms for Pd-Pt bimetallic nanodendrites and their electrocatalytic properties

“…It has been shown that PVP is less effective as a stabilizer in a polar medium such as water [17][18][19]. The small particles have a higher chemical potential due to a large surface area-to-volume ratio, and particle attachment can reduce surface energy by reducing the surface area.…”

Self‐Assembled Heavy Lanthanide Orthovanadate Architecture with Controlled Dimensionality and Morphology

“…[1] In particular, the fabrication of hierarchical and complex nano-/microstructures that assemble from nanoparticles, nanorods, nanoribbons or nanobelts as building blocks at different levels have been proposed and partially realised in recent years. [2][3][4][5] These novel architectures should facilitate a deeper understanding of the "bottom-up" approaches and offer opportunities in searching for exciting new properties of materials, and be useful for fabricating functional nanodevices, and so forth. [5][6][7] Until now, some kinds of compounds or materials, such as metal oxides, [8] sulfides, [7,9] hydrates [10] and other compounds, [11] have been synthesised with controlled hierarchical/complex morphologies by various methods.…”

Electrostatic Co‐Assembly of Iron Oxide Nanoparticles and Polymers: Towards the Generation of Highly Persistent Superparamagnetic Nanorods

“…Since then, other scenarios of controlled clustering of particles have been elaborated. [5][6][7][8][9][10][11] Concerning 3D-assemblies, the realization of ''colloidal molecules'' reminding the spatial regularity of chemical bonds between atoms was made possible using emulsions droplets filled up with colloidal particles [12] or by the control of the density of polymerization nucleation sites at the surface of inorganic colloids. [13] Glotzer and Solomon [14] have reviewed the engineering of anisotropic constructs built on the paradigm of ''bricks and mortar'' suggested by Boal and coworkers.…”