Organometallics directly deposited

Reactivity of Catalysts Derived from Organometallics Directly Deposited on Supports... 

Static and reactive characterization of organometallics directly deposited on supports delineate five parameters which are important in controlling catalytic activity coordinative... 

During the last several years our research group has been involved in the development of a new class of heterogeneous catalysts organometallics directly deposited on high surface... 

MetallorganicMBE (MOMBE). tire solid source Knudsen cells in conventional MBE are replaced witli gaseous beams of organometallic precursors, directed toward a heated substrate in UHV. Compared to MOCVD, MOMBE eliminates gas phase reactions tliat may complicate tire deposition surface reactions, and provides lower growtli temperatures. 

The foam monoliths were a-Al203 samples with an open cellular, spongelike structure. We used samples with nominally 30 to 80 pores per inch (ppi) which were cut into 17 mm diameter cylinders 2 to 20 mm long. A 12 to 20 wt.% coating of Pt or Rh was then applied directly to the alumina by an organometallic deposition. 

Again the organometallic must be carefully chosen to be compatible with the deposition chemistries and temperatures used in the process. This cannot be overemphasized as more complex structures are deposited. The complexity of this task increases when all the reactants are organometallics because the carrier gas (hydrogen) also generally participates directly in the reaction to effectively convert initial radical reaction co-products into neutral, more stable ultimate species. An overview of precursors is provided by Jones [19]. 

Chemical beam epitaxy a process in which one or more beams of volatile metal-organic precursors is directed to the substrate surface to effect film growth Chemical vapor deposition (CVD also termed vapor phase epitaxy) the deposition of a thin film of an element or compound using some form of excitation for the decomposition of a volatile precursor Laser-assisted chemical vapor deposition a CVD in which the excitation is delivered from photons delivered from a laser Metal-organic chemical vapor deposition (MOCVD) the same as CVD, except that the precursor is a volatile organometallic or coordination compound with carbon-containing ligands... 

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