Coprecipitation route

Effect of the Transition Metal Ions - Hexaaluminate materials, 1 >19, including transition metal ions in the structure (M = Mn, Fe, Cr, Co, Ni) were prepared both via the alkoxide15 and the coprecipitation route.23,24,25 For all the compositions investigated, monophasic samples with layered-alumina structure and surface area in the range 10-15 m2/g were obtained upon calcination at 1300 °C. 

Alumina-supported nickel catalysts are an excellent example for the advantages of and the problems associated with coprecipitation processes for the manufacture of catalysts. Such catalysts are accessible via several pathways, as impregnation, deposition/precip-itation, coprecipitation from alumina gels, and more conventional coprecipitation routes. Also, for coprecipitation, different routes are possible, the first examples originating from the 1920s [48]. Starting from the nitrate solutions of nickel and aluminum, there are at least three different routes ... 

A detailed investigation about the chemical and structural composition of maghemite (diameters in the range of 10-20 nm) based MF samples, prepared through the oxidation of magnetite nanoparticle, the latter synthesized by the coprecipitation route, was reported [53]. The precipitate containing the... 

Sohier et al. (1992) compared the hydrogenation properties of catalysts derived from RMC (M-Ni, Cu and Co) intermetallic precursors with those prepared from nitrate mixtures or by coprecipitation of rare-earth and metal hydroxides. These catalysts were also compared to a Ni/CeCh catalyst and mixtures of pure Ni with rare-earth oxide or hydroxides. The intermetallic compounds were submitted to hydriding-dehydriding cycles, then oxidized by calcination at 293 K (partially oxidized) and at 703 K (fully oxidized). The largest surface areas for oxides were obtained by the coprecipitation route. 

It is noted that for CZ samples, the crystallite sizes decreased from 12.5 to -10.9 nm as the calcination temperature was increased from 900 to 1000 °C. This may be due to the occurrence of the phase separation for CZ samples during calcinations within the temperature range of 900-1000 °C, which led to the broadening of XRD diffraction peak The crystallite growth rate of ACZ sample was slower than that of CZ sample (Figure 3). This reveals that the doped Al ions via coprecipitation route could suppress the crystallite growth of Ceo.5Zfo.5O2 effectively. 

Using a one-pot reaction design, an intercalated compound of polyaniline into M0O3 was prepared by Shao et al. [60]. This particular method of synthesis uses a coprecipitation route to fabricate the layered structure. An excess of aniline was acidified to a pH of 0.5, to which was added ammonium molybdate [(NH4)gMo7024.7H20] and FeCl3. The powder pattern of the isolated product revealed the formation of an intercalated phase of polyanihne into M0O3. The identity of the entrapped polymer was confirmed by FTIR... 

Huang Z, Guo W, Fei BJ, Li JT, Cao YG (2013) Influence of sulphate on synthesis of Nd Y2O3 powders via coprecipitation route and fabrication of transparent ceramics. Mater Res Innovations 17 73-79... 

Drying and Calcination of Catalysts Prepared by Comixing/Coextrusion and Coprecipitation Routes... 

A typical laboratory preparation recipe for this coprecipitation route is provided hereafter. The experimental setup consists of a computer-controlled automatic titrator, a syringe pump, and a reactor, heated by a thermostat. 

Oliveira, JM., Costa, SA., Leonor, IB., Malafaya, PB., Mano, IF., Reis, RL. 2009a. Novel hydroxyapatite/ carboxymethylchitosan composite scaffolds prepared through an innovative autocatalytic electroless coprecipitation route. Journal of Biomedical Materials Research 88A 470-480. 

From the two different preparation processes the coprecipitation route does not give the best catalytic activity, due to the fact that these samples have alkaline impurities. The sol-gel method is preferable and leads to very adive catalysts. For the CO + O2 reaction, the LaCoOa catalyst prepared via the sol-gel route showed a temperature of half conversion 100 K lower than for a 2% platinum alumina catalyst (8). 

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