Continuous process for the production of nano-scale metal particles

Abstract

A continuous process for producing nano-scale metal particles includes feeding at least one decomposable moiety selected from the group consisting of organometallic compounds, metal complexes, metal coordination compounds and mixtures thereof into a reactor vessel; exposing the decomposable moiety to a source of energy sufficient to decompose the moiety and produce nano-scale metal particles; and depositing or collecting the nano-scale metal particles.

Description

TECHNICAL FIELD [0001] The present invention relates to a continuous process for the production of nano-scale metal particles useful for catalysis and other applications. By the practice of the present invention, nano-scale metal particles can be produced and collected with greater speed, precision and flexibility than can be accomplished with conventional processing. Thus, the invention provides a practical and cost-effective method for preparing such nano-scale metal particles. BACKGROUND OF THE INVENTION [0002] Catalysts are becoming ubiquitous in modern chemical processing. Catalysts are used in the production of materials such as fuels, lubricants, refrigerants, polymers, drugs, etc., as well as playing a role in water and air pollution mediation processes. Indeed, catalysts have been ascribed as having a role in fully one third of the material gross national product of the United States, as discussed by Alexis T. Bell in “The Impact of Nanoscience on Heterogeneous Catalysis” (...

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Benefits of technology

[0032] In one embodiment of the inventive process, a single feeder feeds a single decomposable moiety into the reactor vessel for formation of nano-scale metal particles. In another embodiment, however, a plurality of feeders each feeds decomposable moieties into the reactor vessel. In this way, all feeders can feed the same decomposable moiety or different feeders can feed different decomposable moieties, such as additional metal carbonyls, so as to provide nano-scale particles containing different metals such as platinum-nickel combinations or nickel-iron combinations as desired, in proportions determined by the amount of the decomposable moiety fed into the reactor vessel. For instance, by feeding different decomposable moieties through different feeders, one can produce a nano-scale particle having a core of a first metal, with domains of a second or third, etc. metal coated thereon. Indeed, altering the decomposable moiety fed into the reactor vessel by each feeder can alter the nature and / or constitution of the nano-scale particles produced. In other words, if different proportions of metals making up the nano-scale particles, or different orientations of the metals making up the nano-scale particles is desired, altering the decomposable moiety fed into the reactor vessel by each feeder can produce such different proportions or different orientations.

[0033] Indeed, in the case of the flow-through reactor vessel, each of the feeders can be arrayed about the circumference of the conduit forming the reactor vessel at approximately the same location, or the feeders can be arrayed along the length of the conduit so as to feed decomposable moieties into the reactor vessel at different locations along the flow path of the conduit to provide further control of the nano-scale particles produced.

Problems solved by technology

One major drawback to the preparation of catalyst materials through loading on a carrier particle is in the amount of time the loading reactions take, which can be measured in hours in some cases.

Thus, these processes are difficult and expensive to operate and also operate in a line-of-sight manner, precluding full use of the support.

Even if technically feasible, however, the Bert and Bianchini methods require high temperatures (on the order of 300° C. to 800° C.)

, and require several hours. A

ccordingly, these processes are of limited value.

However, more significant uses of metal carbonyls are in the production and / or deposition of the metals present in the carbonyl, since metal carbonyls are generally viewed as easily decomposed and volatile resulting in deposition of the metal and carbon monoxide.

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