Thermal Decomposition Methods

Ruthenium is a hard, white metal and has four crystal modifications. It does not tarnish at room temperatures, but oxidizes explosively. It is attacked by halogens, hydroxides, etc. Ruthenium can be plated by electrodeposition or by thermal decomposition methods. The metal is one of the most effective hardeners for platinum and palladium, and is alloyed with these metals to make electrical contacts for severe wear resistance. A ruthenium-molybdenum alloy is said to be... 

Thermal decomposition—Thermal decomposition methods may be used to prepare metal oxide fumes. An aerosol of a precursor to the metal oxide (i.e., a substance that is readily decomposed, thermally, to yield the oxide) is first generated and then is heated by passing it through a heated tube to decompose it to the oxide. Metal formates, oxalates, and the like, which readily yield the oxides and do not produce objectionable side products, are commonly used precursors. In this program, fumes of iron oxide, vanadium oxide, and copper oxide were generated using this method. 

History began for the lithium/SVO cell in 1982, when the first of two U.S. patents for the use of metal vanadium oxides as cathodes in electrochemical cells was granted to Liang et al. [40], Thermal decomposition methods were utilized to... 

Fig. 3.1 Schematic diagram of thermal decomposition method for making DSA type electrodes...

The use of the direct thermal decomposition method has been fairly widespread, and the values obtained by it will be discussed in the appropriate sections of this book. The O - N bond in alkyl nitrates and nitrites, and the G N bond in nitromethane are among those whose dissociation energy has been measured by this method, but in view of the possible kinetic complexities which may be encountered, such as those already mentioned in connection with the pyrolysis of organic iodides (see Section 4.2.4) the values obtained are often at best only tentative. 

The electrochemical synthesis developed by Reetz and co-workers offers at present the most rational method for control of particle size. Researchers have obtained at will almost monodisperse samples of colloidal Pd and Ni between 1 and 6nm using variable-current densities and suitable adjustment of further essential parameters [12]. For thermal decomposition methods the resulting particle size has been found to depend on the heat source [44f]. Size control has also been reported for the sonochemical decomposition method [45e] and y-radiolysis [48]. 

Binder removal can be accomplished by thermal decomposition or by dissolutiion. In ceramics, the thermal decomposition method is commonly used and will be considered here. The process is referred to as thermal debinding or, more simply, as binder burnout. In thermal debinding of ceramic green bodies, both chemical and physical factors are important. Chemically, composition of the binder determines the decomposition temperature and the decomposition products. Physically, the removal of the binder is controlled by heat transfer into the body and mass transport of the decomposition products out of the body. 

This method, which has been applied to the noble metal sulfides, has the advantage that all by-products are easily removed in the flowing gas phase. Both the thermal decomposition method and the direct sulfidation method can be applied to specific sulfides only in cases where the precursor material can be easily synthesized. The low temperature precipitation technique is the only method which can be applied to all the transition metal sulfides. All the above methods easily provide reasonable quantities of high surface area catalysts for further study. 

More descriptively, tar sand is an unconsolidated-to-consolidated sandstone or a porous carbonate rock, impregnated with bitumen. In simple terms, an unconsolidated rock approximates the consistency of dry or moist sand, and a consolidated rock may approximate the consistency of set concrete. Alternative names, such as bituminous sand or (in Canada) oil sand, are gradually finding usage, with the former name more technically correct. The term oil sand is also used in the same way as the term tar sand, and the terms are used interchangeably. The term oil sand is analogous to the term oil shale. Neither material contains oil, but oil is produced therefrom by application of thermal decomposition methods. It is important to understand that tar sand and the bitumen contained therein are different components of the deposit. The recovery of the bitumen, a hydrocarbonaceous material that can be converted into synthetic crude oil (Speight, 1990,... 

W. Chen, J. Zhang, Ag nanoparticles hosted in monolithic mesoporous silica by thermal decomposition method Scripta Mater. 2003,49, 321 -325. 

The thermal decomposition method is very rapid, and the products formed are volatile olefins, alcohols, and fine ceramic powders. 

Another chemical process for obtaining nanosilver is the thermal decomposition method. Its essence is the decomposition of compounds that contain silver in their molecules, and the metal passes in the nano form. The process is possible since silver is characterized by a relatively low decomposition temperature. 

To our best knowledge, the namre of plasma and thermal decomposition methods is not in catalytic form. However, Jin et al. (Zhang, Chang, Fan, Jin, Xu, 2007) reported an innovative catalytic process to decompose CO2 in an 02-permeation MR packed with a mixed-conducting oxide supported noble metal catalyst, Pd/SrCoo.4Feo.5Zro.i03 5 (Pd/SCFZ), which shows high activity in the CO2 decomposition into CO and O2. 

In the thermal decomposition method, upon heating above 200°C, zirconyl chloride dihydrate loses its hydratation water as follows ... 

Figure 5 TEM images of upconversion nanocrystals. (a), (b) Ultrasmall LaF3 Yb/Er nanoparticles prepared by Yi and Chow via coprecipitation method, (c), (d) 8-NaYF4 Yb/Er nanoparticles and nanoplates prepared by Yan et al via thermal decomposition method, (e), (f) a-NaYF4 Yb, Er nanoparticles prepared by Capobianco et al via thermal decomposition method, (g), (h) NaYF4 Yb r nanoparticles and nanorods prepared by Wang and LP via hydrothermal method. (Reproduced from Ref. 3 with permission of The Royal Society of Chemistry.)...

An example of ligand exchange involves the use of poly-(ethylene glycol) (PEG-600) dicarboxy acid. Yi and Chow first prepared oleyamine stabilized /3-NaYF4 Yb/Er nanoparticles by thermal decomposition method and subsequently used PEG-600 dicarboxy acid to replace surface oleylamine moieties. The carboxyl group on one end of PEG-600 diacid can be covalently attached to UCNPs and... 

Melsheimer J, Ziegler D. The oxygen electrode reaction in acid solution on RUO2 electrode prepared by the thermal decomposition method. Thin Solid Films 1988 163 301-8. 

---