High temperature aerosol decomposition

Hydrocarbon Partial Oxidation Catalysts Prepared by the High-Temperature Aerosol Decomposition Process Crystal and Catalytic Chemistry... 

Figure 1. Aerosol process configuration for the continuous preparation of metal oxides by the High Temperature Aerosol Decomposition (HTAD) Process.

Moser, W. R., Reactor for High-Temperature Aerosol Decomposition and Catalysts and Other Materials Obtained, PCT Int. Appl., Assigned to Worcester Polytechnic Institute (1991). 

Moser, W. R., Hydrocarbon partial oxidation catalysts prepared by the high-temperature aerosol decomposition process, in Catalytic Selective Oxidation, ACS Symp. Ser. (S. T. Oyama and J. W. Hightower, Eds.), pp. 523,244 (1993). 

Moser, W. R., Knapton, J. A., Koslowski, C. C., Rozak, J. R., and Vezis, R. H., Noble metal catalysts prepared by the high-temperature aerosol decomposition (HTAD) process, Catal. Today 21,157 (1994). 

Moser, W. R., Lennhoff, J. D., Cnossen, J. E., Fraska, K., and Rozak, J. R., The high-temperature aerosol decomposition process A general method for the synthesis of complex catalysts. Preprnt. Petroleum. Div., Amer. Chem. Soa 40(1), 49 (1995). 

High temperature aerosol decomposition, catalyst synthesis, 3 Hydrodynamic cavitation advanced catalysts, ceramics, and electronic materials, 3, 6-bismuth molybdate, 33-34 Bernoulli effect, 22... 

Evaporative decomposition erf solutions and spary pyrolysis have been found to be useful in the preparation of submicrometer oxide and non-oxide particles, including high temperature superconducting ceramics [819, 820], Allowing uniform aerosol droplets (titanium ethoxide in ethanol, for example) to react with a vapor (water, for example) to produce spherical colloidal particles with controllable sizes and size distributions [821-825] is an alternative vapor phase approach. Chemical vapor deposition techniques (CVD) have also been extended to the formation of ceramic particles [825]. 

Rather than produce an atomic vapor by evaporation from a solid surface, an aerosol may be generated from an aqueous salt solution by an atomization procedure. The aerosol can then be evaporated so that the salt condenses into a particle. This is known as the spray-pyrolysis technique. The flame decomposition method is a modification of this technique, in which the aerosol is introduced into a high-temperature flame (1200-3000 K). The precursor is vaporized and oxidized to form metal-oxide particles. 

Hot wall reactors involve aerosol precursor synthesis (usually aerosols of liquid droplets) and the subsequent decomposition in a high-temperature flow reactor in order to form the desired aerosol products (usually aerosols of solid particles). This method has been used to prepare soot particle aerosols and also a variety of metal oxide aerosols, including aerosol phosphors [47]. 

The liquid aerosol thermolysis involves the decomposition of aerosolized solution in high temperature. 

Aerosol spray pyrolysis is another method used to control particle size by limiting the local environment around the particle nucleation sites. In aerosol spray pyrolysis, metal salt solutions are first aerosolized with a carrier gas and then heated in a high-temperature furnace to remove the solvent and form oxides. Heating metal salts to very high temperatures in air results in decomposition of the salts and subsequent formation of metal oxides. 

In addition to the high-temperature region of the annular plasma, there are also other operationally defined zones (1) the initial radiation zone (IRZ), in the axial channel aligned with the RF load coil (2) the normal analytical zone (NAZ), which is located immediately above the IRZ (usually 10-20 mm) and (3) the preheating zone (PHZ), which is located in the axial channel before reaching the plasma. These zones are shown in Figure 3.9. Solvent vaporization and dry aerosol decomposition to individual molecules or species usually occurs in the PHZ prior to the sample entering the plasma. Atomization or decomposition of crystalline materials and dissociation of molecules occurs in the IRZ. Finally, ionization of atomic species, produced in the IRZ, occurs in the NAZ. 

Even though all three reactors share the same precursor delivery system, each tool offers specific advantages. For example, a cold-wall reactor (reactor B) helps prevent decomposition of the precursor before it reaches the substrate. A pulsed aerosol injection system at low pressure (reactor C) allows the film to grow under better-defined conditions than in a continuous process (reactor A) because of the minimization of undesirable transient effects caused by the high volatility of the solvents used.46 A more detailed description of each of the conditions for film growth, including reactor type, precursor type, delivery method, deposition temperature, growth time, and other parameters are summarized in Table 6.2. Depositions were done on bare and Mo-coated... 

In an extension of the spray-drying technique called spray roasting , evaporative decomposition of solutions (EDS) , spray pyrolysis , or aerosol pyrolysis , the temperature of the heated chamber is high enough to decompose the dried salts after the solvent has evaporated. Nitrate salts are used because of their low decomposition temperatures. The technique eliminates the problems of handling dried nitrate powders, which can be hydroscopic. These methods are used to prepare chalcogenide powders" and barium titanate . 

The chemical features of tin(IV) alkoxides, such as pre-existing metal-oxygen bonds in molecular units, high volatility and low decomposition temperatures make them attractive precursors for deposihon of Sn02. The heterometallic complex [Sn(dmae)2Cd(acac)2],Figures.1.2, (acac = 2,4-pentanedionato dmae = N,N -dimethylamino-ethanoate) has been decomposed in aerosol-assisted chemical vapor deposition conditions, producing amorphous tin(IV) oxide films with no detectable cadmium. ... 

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