Deposition metal oxides

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Porous metal oxide deposits also permit the development of high boiler water concentrations. Water flows into the deposit and heat appHed to the tube causes the water to evaporate, leaving a concentrated solution. Again, corrosion may occur. Caustic attack creates irregular patterns, often referred to as gouges. Deposition may or may not be found in the affected area. 

Anode Applications. Graphite has been used as the primary material for electrolysis of brine (aqueous) and fused-salt electrolytes, both as anode and cathode. Technological advances, however, have resulted in a dimensionally stable anode (DSA) consisting of precious metal oxides deposited on a titanium substrate that has replaced graphite as the primary anode (38—41) (see Alkali and chlorine products). 

Poor housekeeping with uncontrolled metal oxide deposition usually increases the rate of corrosion. 

After heating, the EB is mixed with superheated steam and fed to the first stage reactor. Both the first and second stage reactors are packed with a catalyst of metal oxide deposited on an activated charcoal or alumina pellets. Iron oxide, sometimes combined with chromium oxide or potassium carbonate, is commonly used. 

Both heterogeneous and homogeneous disproportionation catalysts are known. All contain a transition metal component with derivatives of Mo, W, and Re being the most important. Heterogeneous catalysts are generally metal oxides deposited on a support such as silica or alumina (1, 4). Homogeneous catalysts in general require a non-transition metal derivative as cocatalyst (2, 3). 

These results parallel those found on the V20,/Si02 system where O was formed by adsorption (72). The photoreactivity of transition-metal oxides deposited onto PVG or silica supports has been investigated by several authors (71b-7Ie) and is discussed in more detail in Section VI,C under reactivity of the lattice oxygen ions. 

Interest in the composition and structure of submonolayer metal oxide deposits on metals has developed as a consequence of growing evidence that such deposits influence the adsorptive and catalytic properties of the substrate metal [see for example ref. (1)]. In particular, it has been shown that titania deposited on a Ni(l 11) (2) surface and on the surface of Pt and Rh foils (3.41 will enhance the activity of the metal for CO hydrogenation. Similar results have also been reported for niobia deposited on a Pt foil (5). Hie present paper discusses the characterization of titania overlayers deposited on the surface of a polycrystalline Rh foil and a Rh(lll) surface. 

In this section various existing lanthanide and actinide metal-organic enolate precursors for rare earth metal oxide deposition are discussed and the rationale of their selection is addressed. CVD, ALD and ultrasonic spray pyrolysis (USP) of the lanthanide or actinide enolate starting materials has been carried out under a variety of conditions as can be seen from Table 7. 

This section provides a comprehensive tabular summary of mixed metal oxide deposition, complementary to the books edited by Rees Jr. and by Jones and O Brien, focusing on the literature dealing with metal enolate precursors published after 1996. 

If the support has a hydrophilic surface, e.g., glass and metal (oxides), deposition follows the sequence of events depicted in fig. 3.53. On the first downward stroke... 

Inorganic Metal oxide materials Base single or mixed metal oxides Deposition method and conditions of base metal oxide(s) Annealing method and conditions Dopant(s) Doping method and conditions Purity of materials... 

Chemical bonds, covalent or ionic as shown in Figure 6c and d, at the metal oxide/deposit surface are potentially strong with theoretical values over 10 N m. it is however, impossible to estimate the number of sites and the size of contact areas at the interface where the chemical bonds may be effective. In any case, the cohesive strength of the deposit matrix is the limiting factor since it is lower than that of chemical bonds by several orders of magnitude. In practice, this means that when a strongly adhering deposit is subjected to a destructive force, e.g. sootblower jet, failure occurs within the deposit matrix and there remains a residual layer of ash material firmly bonded to the tube surface. 

MO c a metal oxide deposited on the electrode surface. In X ysurt... 

The catalyst is a mixture of metallic oxides deposited in a fixed bed in a multi-tube reactor and operating in the vapor phase. The beat of reaction is removed by the circulation of molten salts. Conversion takes place at 450 to 500 C, at 0.1. 10 Pa absolute, with YHSV ranging from 1000 to 4000 h. Once-through conversion ranges from 90 to 100 per cent and yield from 70 to 80 molar per cent One unit is in operation in Japan. 

In this paper we present research on SILD technology for deposition of the mentioned above porous nanostructured SnOz layers. Last years the SILD technology excites high interest, because this method of metal oxide deposition is simple, inexpensive, and gives possibility to deposit thin nanostructured films on rough surfaces [1]. 

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