Impregnated support

The preparation of catalysts usually involves the impregnation of a support with a solution of active metal salts. The impregnated support is then dried, calcined to decompose the metal salt and then reduced (activated) to produce the catalyst in its active form. Microwaves have been employed at all stages of catalyst preparation. Beneficial effects of microwave heating, compared with conventional methods, have been observed especially in the drying, calcination, and activation steps. 

Simple refractory oxides such as alumina have also been shown to promote chemical transformations(14). Displacement and oxidation reactions(15) as well as desulfurizations(16) and oxidative couplings (17) are enhanced through the use of impregnated supports. The main advantages observed in this area are again improved selectivi-ties, reactivities, and simplified separations. 

This catalyst was prepared by impregnating y-Al203 with a Ni(N03)2 and La(N03)3 solution. By drying and calcinating the impregnated support we then obtained a system of monolayer-dispersed NiO and La203 on... 

Three different pretreatments were performed and studied by both Quick EXAFS and MS. During each pretreatment the impregnated support was heated in one gas with a ramp of 2°C/min from room temperature to 400°C. The gases used were 1) either He (QEXAFS) or Ar (MS) (this sample is called Pt[Ar/He] ), 2) 02 ( Pt[02] ) and 3) H2( Pt[H2] ). 

Non impregnated Support Sorbent Composition / calcination conditions Ferrite (as oxides) % added Method... 

In the case of vapour-phase processes for metal deposition on the support, only limited control of dispersion and distribution of the metal crystallites is possible. In the case of liquid-phase systems, they do not provide as wide a range of catalysts as is possible with techniques based on adsorption from solution. However, the technique does provide a means of preparing well characterized surface-impregnated supports. 

The whole apparatus is placed into a thermostatted furnace which is being washed with neutral gas in order to remove products of electrolysis. The electrodes are made of metals which can withstand the drastic conditions of the procedure, platinum for the anode and tungsten, nickel, copper or graphite for the cathode. The impregnated support (fibreglass paper) is equilibrated for about 1 h with the molten salt before the actual electrophoresis. The sample is applied from a capillary that can be moved from the outside of the furnace. 

The primary method for dispersing PFIEP is by impregnating supports with alcoholic solutions of soluble PFIEP in the acid form. Alternatively, the polymeric sulfonyl fluoride precursor is a thermoplastic and can be extruded into thin films or blended with a powder support and extruded into various shapes (69). In addition, the sulfonyl fluoride precursor can be coextruded with a polyethylene resin to form differently shaped parts (70). 

A 12.7%Co/Si02 catalyst was prepared by incipient wetness impregnation of silica (PQ Corporation, CS-2133 treated in dry air at 400°C for 3 hours). The impregnated support was dried at 60°C. The catalyst was reduced in H2 directly, without calcination, at 350°C for 1 hour. The catalyst was passivated in 1%02/He at room temperature. 

Biloul, A., O. Contamin, G. Scarbeck, M. Savy, D. van den Ham, J. Riga, and J.J. Verbist (1992). Oxygen rednction in acid media Effect of iron substitution by cobalt on heat-treated naphthalocyanine impregnations supported on preselected carbon blacks. J. Electroanal. Chem. 335, 163—186. 

Figure 1 shows a typical apparatus for flatbed electrophoresis. It is fabricated from glass or fused silica. An electric field is applied to the impregnated support by two electrodes immersed in separate reservoirs at either end of the support. The choice of... 

With active precursors that do not significantly adsorb on the surface of the support, pore-volume (incipient wetness) impregnation leads to a uniform distribution of the solution of the precursor throughout the pore system of the support. It is highly relevant to investigate whether subsequent drying of the impregnated support results in a nonuniform distribution of the aetive component. 

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