Oxide catalysts, preparation

Thammachart M, Meeyoo V, Risksomboon T, Osuwan S (2001) Catalytic activity of Ce02-Zr02 mixed oxide catalysts prepared via sol-gel technique CO oxidation. Catal Today 68 (1) 53—61... 

Comparison of promoted alkaline-earth oxide catalysts prepared through evaporation and sol-gel methods by their catalytic performance in propane oxidative dehydrogenation... 

Platinum oxide catalyst prepared by the method of K. Adams has recently come into use because it is very convenient to prepare and handle and at the same time has very high activity. When in use it is first reduced by hydrogen in the hydrogenation bulb to very finely divided platinum. 

B. (1998) A study of the structural and catalytic effect of sulphation on iron oxide catalysts prepared from goefhite and ferrihydrite precursors for methane oxidation. Catalysis Letters 53 7—13... 

Hydrocarbon Partial Oxidation Catalysts Prepared by the High-Temperature Aerosol Decomposition Process Crystal and Catalytic Chemistry... 

Figure 4. X-Ray diffraction patterns for phosphorous-vanadium oxide catalysts prepared by aerosol technique at 600 C, 8 seconds residence time, and 0.8 M V in feed a. Catalyst analyzed by XRD immediately after synthesis, b. catalyst calcined at 450°C in nitrogen for 3 hrs immediately after synthesis, c. Catalyst allowed to stand for 14 days in an air tight container at ambient temperature without calcining.

Active crystal face of vanadyl pyrophosphate for selective n-butane oxidation catalyst preparation, 157-158 catalyst weight vs. butane oxidation, 162,163/ catalytic activity, 162,1 (At catalytic reaction procedure, 158 experimental description, 157 flow rate of butane vs. butane oxidation, 162,163/ fractured SiOj-CVO PjO scanning electron micrographs, 160,161/ fractured scanning electron... 

As to the method of preparation, it was found that V-Mg oxide catalysts prepared with a Mg(OH)2 precursor that was precipitated with KOH was less selective than one prepared with a MgC03 purecursor precipitated with (NH4)2C03 (25). Interestingly, unlike the butane reaction, there was no effect of preparation on the oxidative dehydrogenation of propane using the same catalysts, as mentioned earlier (25, 30). Unlike the oxidation of propane, Mg pyrovanadate was nonselective for butane (25, 26). Mg metavanadate was nonselective as well (26). 

Daniel and Keulks (104) investigated Bi-Fe-Mo oxide catalysts prepared by reacting the a-bismuth molybdate with ferric hydroxide. Comparison of these catalysts with bismuth molybdate and ferric oxide indicated that mechanistically the Bi-Fe-Mo oxide catalysts resembled bismuth molybdate in their ability to form an allyl species. Under the same reaction conditions, the composition with Bi-Fe-Mo atomic ratio equal to 6 9 10 exhibited higher conversion than and the same selectivity as the bismuth molybdate catalysts. In contrast to bismuth molybdate, the Bi-Fe-Mo oxide catalysts were found to maintain their activity and se-... 

Moser, W. R., Hydrocarbon partial oxidation catalysts prepared by the high-temperature aerosol decomposition process, in Catalytic Selective Oxidation, ACS Symp. Ser. (S. T. Oyama and J. W. Hightower, Eds.), pp. 523,244 (1993). 

Table 4.5 Characteristics of Au/oxide catalysts prepared by deposition of phosphine gold complexes.

Table 4.6 Characteristics of Au/oxide catalysts prepared by deposition of Me2Au(acac) in acetone (nominal Au loading in solution 3wt.%).90...

The most common method for mixed-oxide catalyst preparation is crystallization or precipitation or copre-cipitation in solution of a precursor form (hydroxide,... 

Kolen ko YV, Amakawa K, Naumann d Alnoncourt R, Girgsdies F, Weinberg G, Schlogl R, Trunschke A. Unusual phase evolution in MoVTeNb oxide catalysts prepared by a novel acrylamide-gelation route. ChemCatChem. 2012 4(4) 495-503. 

Trombetta, M., Ramis, G., Busca, G., Montanari, B. and Yaccari, A. (1997). Ammonia adsorption and oxidation on Cu/Mg/Al mixed oxide catalysts prepared via hydrotalcite-type precursors. Langmuir 13, 4628. 

Figure 19 shows the typical photoluminescencc spectrum of the anchored vanadium oxide catalyst prepared by photo-CVD methods (a), its corresponding excitation spectrum (b), and the UV absorption spectrum of the catalyst (c) (56,115,116). These absorption and photoluminescence spectra (phosphorescence) are attributed to the following charge-transfer processes on the surface vanadyl group (V=0) of the tetrahedrally coordinated VO4 species involving an electron transfer from to V and a reverse radia-... 

The results obtained with vanadium oxide catalysts prepared by the impregnation method show a remarkable contrast with those obtained with anchored vanadium oxide catalysts (63,116). As shown in Fig. 64. the yields of the photocatalytic isomerization as well as the yields of the phosphorescence of the oxide increase with the content of the vanadium ions and then decrease, even when the catalyst contains 0.1 wt% V. When the vanadium content is high, an increase in the efficiency of the radiationless deactivation due to the aggregation of the vanadium oxide species is observed. 

The addition of Cu to K/Fe oxides catalyst enhanced its ability of ethanol production. K/Cu-Fe oxides catalysts, prepared by kneading KjCO, with Cu-Fe co-precipitate, gave the ethanol selectivity of more than lOC-% at 300°C. The combination of K/Fe and Cu-Zn gave remarkable results on ethanol production. In the reaction over K/Cu-Zn-Fe oxides catalyst, CO2 conversion of 44% and ethanol selectivity of 20C-% were obtained under the standard reaction conditions. Besides ethanol, hydrocarbons were produced with a selectivity of almost 45C-%. The formation of hydrocarbons seems inevitable as long as Fe-based catalysts are employed. 

Photocatalytic reduction of CO2 with H2O on Ti/Si binary oxide catalysts prepared by the sol-gel method... 

Moon S.-C., Fnjino M., Yamashita H. and Anpo M. (1997), Characterisation of zirconinm-silicon binary oxide catalysts prepared by the sol-gel method and their photocatalytic activity for the isomerization of 2-butene, J. Phys. Chem. B 101, 369-373. 

Oxidation Catalysts Prepared by Mechanically and Thermally Induced Spreading of Sb203 and V2O5 on Ti02... 

Figure 4. Laser raman spectra of Mo=0 species in the complex Mo-Ce oxide catalysts prepared by different methods, (a) Mo-Ce(cp), (b) Mo-Ce (sg).

I.Z. Ismagilov, R.P. Ekatpure, L.T. Tsykoza, E.V. Matus, E.V. Rebrov, M.H.J.M. De Croon, M.A. Kerzhentsev, J.C. Schouten, Optimization of anodic oxidation and Cu-Cr oxide catalyst preparation on structured aluminum plates processed by electro discharge machining, Catal. Today 105 (2005) 516. 

Marchenko L.S., Zhuk S.Ya., Kir yakov N.V., Nersesyan M.D., Grigoryan E.H., Oxidative Dehydrodimerization of Methane Over Complex Oxide Catalysts Prepared by Self-Propagating High-Temperature Synthesis, Catal. Today, 13 (1992) 593. 

Oxidation. Catalyst preparation procedures determine catalyst structures and consequent catalytic performance. The activity of combinations of oxides is often quite different from those of the individual oxides. For example, the capability of FejOj, the catalyst used to oxidize CH3OH to formaldehyde, to promote complete oxidation is nearly absent in iron(III) molybdate, Fe2(Mo04>3. ... 

In the presence of zinc oxide catalysts prepared by precipitation from a zinc sulfate solution the proportion of dehydration and dehydrogenation... 

A comparison, however, of zinc oxide catalysts prepared in different ways, i.e. (A) precipitation of zinc hydroxide from zinc sulfate, (B) dry process commercial zinc oxide, and (C) hydrolysis of zinc isopropoxide in moist air, showed that the mode of preparation had a marked effect on the catalyst action. The percentage of olefin formed at a given temperature varied from 5 to 88 for isopropanol, 10 to 20 for ethanol, 1 to 31.5 for isobutanol, and 2 to 15 for n-propanol and butanol. In general, catalyst A was best for dehydration, and catalyst B for dehydrogenation, except in the case of ethanol where they were about the equal. Catalyst C behaved about the same as B, except in the case of ethanol, in which case it was a better dehydration material. 

In the early literature it was reported that Si02-Al203 [10,11] and supported tungsten oxide [11] had high activity and selectivity for -caprolactam. Tungsten oxide catalysts prepared from the hydrolysis of WClg and supported on silica gel were more caprolactam selective than the catalyst prepared from ammonium tungstate... 

Silica-supported Ta oxide catalyst prepared by the reaction between Ta alk-oxide and surface hydroxy groups of Si02 had higher catalytic efficiency than catalysts prepared by impregnation with TaClj or hydrated tantalum oxide [13]. Pt/ sulfated Zr02 is reported in a patent to be active and durable [14],... 

The stability of CuO is dependent on the quality of the carrier. It was established that the specific surface area of the carrier has little effect. Copper oxide catalysts prepared on A3 (250 m2/g), Cl (90 m2/g), and El (10 m2/g) had similar activity after calcination at 1000°C. On... 

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