Paper NS-TuM2
Plasma-assisted Dissociation of Organometallic Vapors for Continuous, Gas-Phase Preparation of Multimetallic Nanoparticles

Tuesday, November 1, 2011, 8:20 am, Room 203

Metal nanoparticles (NPs) are desired for novel optical, magnetic, electric, and catalytic applications. Recently, there has been growing interest in multimetallic NPs, a special class of metal NPs composed of two or more distinct metal elements with alloyed, core-shell, or other architectures. Despite the development of numerous synthetic routes for metal NP synthesis, the preparation of multimetallic NPs with controlled size, composition, morphology, and purity remains a significant challenge.

Here, we present a single-step, continuous, gas-phase process that is capable of producing a wide range of size- and compositionally-tuned multimetallic NPs [12]. Our approach is based on plasma-assisted dissociation of metal-organic vapors which is a well-established technique for chemical vapor deposition (CVD) of thin films of metals. In our case, these same precursors are dissociated in a continuous-flow, atmospheric-pressure microplasma to homogeneously nucleate metal NPs. To synthesize multimetallic NPs, more than one precursor is mixed in the microplasma reactor. The size of the multimetallic NPs is controlled by the total vapor concentration of the precursors while the atomic-scale composition is controlled by the relative ratio of the different metal precursors. Bimetallic and trimetallic NPs of various metals including Ni, Fe, Cu, and Pt, have been produced by this approach. In this talk, we will discuss our experimental method in detail, as well as the structural properties of the NPs as determined by in situ aerosol measurements, high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD).

References

1. W-H. Chiang and R.M. Sankaran, Adv. Mater. , 4857 (2008).

2. P. A. Lin and R. M. Sankaran, submitted.