Traditional solid-state synthesis technique

Pt and Pd nitride nanoparticles have been synthesized by sputtering of the parent metal with N2 plasma [85]. Traditional solid-state synthesis techniques are often unsuccessful in creating Pt/Pd nitrides due to the low M-N bond strength. Physical vapor deposition processes such as sputtering can, however, often produce materials that are not expected thermodynamically due to the nature of the reaction. In this study, platinum and palladium thin films and nanoparticles were... 

A major drawback connected with the symproportionation reaction is that the number of redox reactions that can take place is limited. A more recent development, which shows obvious similarities to the traditional molten salt route, but whieh avoids the limitations of symproportionations, is the solid-state technique developed by Beck in which a volatile, high-valent transition-metal chloride acts both as halide acceptor and as oxidizing agent. The synthesis of Tes " by oxidation of tellurium with WCl6 according to (4) is representative. ... 

Powder synthesis using the alkoxy precursor technique exhibits processing flexibility not available in traditional high-temperature solid-state reaction of the mechanically mixed and milled oxides and/or the inorganic salt constituents. With proper process control, impurities can be reduced to very low levels, yielding the desired electrical, optical, thermal, and mechanical properties. In addition, selected elements may be purposely added in controlled amounts to influence these properties. 

Since then, HP became a widely used technique to prepare transparent spinel ceramics. For example, HP process was used to fabricate MgAl204 transparent ceramics, with a nearly 100 % densification [44]. Spinel powders for the production of transparent polyciystalline ceramic windows were produced by using both the traditional ceramic solid-state reaction and solgel methods. Among them, the powders produced from the reaction of organomagnesium compounds with surface modified boehmite precursors were best to produce high-quality transparent spinel ceramics. The powder synthesis method allowed fine control over the particle size. 

We will describe the current state-of-the-art of the microemulsion method for the preparation of metal-based catalysts. First, some general considerations concerning the nature of a microemulsion and its relation to the preparation of particles will be given. Then, both the preparation of solid oxides and metal-supported catalysts by microemulsion will be detailed. When possible, the properties of the solids prepared by microemulsion will be compared with those of their counterparts prepared by traditional techniques. Particular attention will be paid to the description of the catalytic properties of these solids. There is a large body of work in the field of organic synthesis, and enzyme catalysis in which microemulsion techniques play an important role. However this topic is not included in this paper, for that purpose several reviews are available, see for example those by Holmberg and Lawrence Rees... 

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