Flame spray pyrolysis

Flame spray pyrolysis (FSP) a liquid precursor solution is sprayed into the flame and ignites its combustion drives the flame process. 

Preparation of titania nanopartidei of anatase phase by using flame spray pyrolysis... 

In this work, flame spray pyrolysis was applied to the synthesis of titania particles to control the crystal structure and crystallite size and compared with the particle prepared by the conventional spray pyrolysis... 

Fig. 3. XRD patterns of titaoia particles prqmied by flame spray pyrolysis with various flame tecD eratur. ...

Another distinguishing feature of titania prepared by flame spray pyrolysis is the draar e of anatase crystallite size with the increase of flame temperature. Generally, the increase of preparation temperature increases the crystallite size in other processes such as sol-gel method, hydrothermal method [2, 3], flame processing and conventional spray pyrolysis. The decrease of crystallite size was directly related to the decrease of particle size. Fig. 5 shows SEM and TEM images of titania particles prepared by flame spray pyrolysis. 

Fig. 6. Comparison of initial rate with titama particles prepared by flame spray pyrolysis and spray pyrolysis.

Compared with the conventional spray pyrolysis, flame spray pyrolysis produces titania particles that are strikingly different in crystd phase and surfece arra. The fraction of anatase phase increases with the increase of flame tempCTature while it decreases with the increase of preparation temperature in the conventional spray pyrolysis. The sur e area and... 

Madler L, Kammler HK, Mueller R, Pratsinis SE (2002). Controlled synthesis of nanostructured particles by flame spray pyrolysis. J Aerosol Sci 33 369 -388... 

Mueller R, Madler L, et al (2003) Nanoparticle synthesis at high production rates by flame spray pyrolysis. Chemical Engineering Science 58(10), 1969-1976... 

FIGURE 10.6 Result of the fitting using the fundamental parameter approach in ZnO/Si02 powder (2 1). The black and gray lines correspond to the measured and calculated XRD patterns, respectively. (From Tani, T., Madler, L., and Pratsinis, S.E., Synthesis of zinc oxide/silica composite nanoparticles by flame spray pyrolysis, J. Mater. Set, 37, 4627, 2002.)... 

J. Marchal et al., Yttrium aluminum garnet nanopowders produced by liquid-feed flame spray pyrolysis (LF-FSP) of metalloorganic precursors. Chem. Mater. 16(5), 822-831 (2004). 

A series of catalysts for the low temperature WGS reaction has been prepared by flame spray pyrolysis. The catalysts consist of a traditional Cu/Zn0/Al203 sample, a ceria promoted Cu/Zn0/Al203 catalyst and a series of ceria and/or zirconia supported Cu or Pt catalysts. Flame spray pyrolysis results in high surface area catalysts with good dispersion. The WGS activity of the catalyst samples has been measured in a plug-flow reactor in the temperature range 180-315 °C. ... 

The properties of the catalyst particles depend on the conditions used in the flame spray pyrolysis. For example the BET surface area for an alumina sample could be varied between 140-240 mVg by changing the precursor flow from 140... 

Table 1 The catalyst samples made by flame spray pyrolysis.

The behavior of the catalysts prepared by flame spray pyrolysis has also been compared with a commercial catalyst (unknown composition but consisting of CuZnO/support). A higher conversion is obtained with the commercial sample in particular at low temperatures, but the difference decreases with increasing temperature. 

The commercial catalyst discussed above was also studied as a function of time on stream. The conversion decreased at about the same rate as for the CuZnAl sample prepared by flame spray pyrolysis. After 25 hours on stream the commercial sample and the CuZnCeAl have almost the same conversion level. 

Only small amounts of the samples were prepared in this case by the flame spray pyrolysis unit since it was only a first screening. It is therefore difficult to perform detailed characterization of each catalyst, but the next step is to produce larger amounts of the most promising samples. 

It has been shown that flame spray pyrolysis can be used to produce metal-oxide catalysts with large surface areas. The surface area is strongly influenced by the flame conditions and the burner design. The properties of the final particles can be designed by changing the conditions during the synthesis. 

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