Perovskites preparation

Ding X, Liu Y, Gao L, and Guo L. Synthesis and characterization of doped LaCrOs perovskite prepared by EDTA-citrate complexing method. J. Alloys Compounds 2007 458 346-350. 

Copper high Miller index, 26 12 Copper oxide, 27 184-187, 199 as adsorbent, 21 44 on alumina, 27 80-85 -manganese oxide, 27 91, 92 oxidation of CO over, 24 86 -platinum catalyst, 27 86-88 propylene oxidation, 30 141 Coprecipitation, perovskite preparation, 36 247-250... 

Cordierite-supported perovskites, preparation impregnation, 36 251-253 plasma spraying, 36 253 Core electron kinetic energy of, 34 211 spectra of, 34 210... 

Double Heck reaction, 42 494 Double layer interface, 30 223-225 Double nucleophilic displacement, capped cyclodextrin, 32 437 Double-pulse method, 38 31 Double recognition models, 32 451 52 Doublet mechanisms, 30 43, 45, 47 Drago parameters, 38 212 Drougard-Decrooq equation, 30 345, 356, 371 Dry evaporation, perovskite preparation, 36 246-247... 

The TPR profiles of five Co-based perovskites prepared by reactive grinding with ZnO as additive for different milling times are shown in Figure 4(a-e), Figure 4f represents a LaCoOs perovskite prepared by the citrate method (referenee sample). 

Three series of LaCoi. CuxOs, LaMni.xCuxOs, LaFei x(Cu, Pd)x03 perovskites prepared by reactive grinding were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed desorption (TPD) of O2, NO + O2, and CsHg in the absence or presence of H2O, Fourier transform infrared (FTIR) spectroscopy as well as activity evaluations without or with 10% steam in the feed. This research was carried out with the objective to investigate the water vapor effect on the catalytic behavior of the tested perovskites. An attempt to propose a steam deactivation mechanism and to correlate the water resistance of perovskites with their properties has also been done. 

Ciambelli, P Cimino, S Lisi, L Faticanti, M Minelli, G Pettiti, 1 Porta, P. La, Ca and Fe oxide perovskites preparation, characterization and catalytic properties for methane combustion. Appl Catal, B Environmental, 2001, Volume 33, Issue 3, 193-203. 

Zhang, RD Alamdari, H Kaliaguine, S. SO2 poisoning of LaFeo sCuo 2O3 perovskite prepared by reactive grinding during NO reduction by CsH , Appl Catal A General, 2008, Volume 340, 140-151. 

Ozaki [1245] in his review classified perovskites prepared from metal alkoxides according to conditions of their crystallization. He described the following three possibilities of crystallization of perovskites (1) direct crystallization in the course of hydrolysis, (2) one-step process of thermal treatment of the amorphous hydrolysis products, and (3) crystallization as a result of the solid-state reactions between the first crystallized oxides. At present, it has become evident that the careful choice of processing conditions (which includes pre-hydrolysis and hydrolysis stages) allows most of the perovskites enumerated by Ozaki to be obtained without thermal treatment after hydrolysis. If the thermal treatment is, nevertheless, necessary, it is important to choose the appropriate atmosphere (air, oxygen, or oxygen-water vapor flow). 

L.A. Isupova, S.V. Tsybulya, G.N. Kryukova, G.M. Alikina, N.N. Boldyreva, A.A. Vlasov, O.I. Snegurenko, V.P. Ivanov, V.N. Kolomiichuk, V.A. Sadykov, Physicochemical and catalytic properties of Lal-xCaxFeO3-0.5x Perovskites prepared using mechanochemical activation, Kinet. Catal. 43 (2002) 129. 

In Section II the perovskite and related structures are briefly introduced. In Section III the methods most frequently used for perovskites preparation are described comparatively. Sections IV, V, and VI refer to the bulk and surface properties of perovskites. Some of these properties will facilitate understanding of the catalytic action of these compounds. Section VII includes a review of the reactions where perovskite oxides were used as catalysts. Some of them are described separately (Sections VII,A-H). These include reactions that were more extensively studied or reactions that may have an increasing interest in the near future. Section VII,I includes less studied reactions such as oxygen homomolecular exchange, hydrogen and NH3 oxidations, N20 decomposition and dehydro-... 

Wachowski et al. (42,43) have compared the surface areas of a series of eight perovskites prepared by different methods ceramic (<2.4 m2/g), coprecipitation as oxalates (4.5-11 m2/g), explosion (21-37 m2/g), and freeze-drying (22-39 m2/g). Again, surface areas clearly depended on the minimum temperature necessary for complete reaction. The greatest losses in surface area by sintering were observed in the temperature range 700-930°C. 

Catalytic Properties of Strontium Ruthenate Perovskite Prepared by Hot Isostatic Pressure Method... 

Tin containing perovskites ASnOs (A = Ca, Sr, Ba) are prepared by a soL gel method starting from tin oxygenated precursor (SnO) or from chlorinated precursors (SnCU). The respective reactivity tests in oxidative coupling show that perovskites prepared from chlorinated precursors have a mudi higher C2 hydrocarbons selectivity than that obtained from oxygenated ones (70% compared to 40% for BaSnOs). This difference in reactivity is interpreted by the modification of the basicity of the system by bulk or surface chlorine (CO2 thermodesorption). 

Scheme 1. Summarized ASnOs perovskite preparation (A Ca,Sr3a) by sol-gel method. (I) Oxygenated precursor H) Chlorinated precursors.

The present work was undertaken to develop the methods of active powdered perovskites preparation via mechanical activation, as well as to shape monoliths by extrusion and to investigate their catalytic properties and stability. 

Catalytic properties of perovskites prepared via mechanical activation route influence of defect structure and surface segregation... 

Two types of study were undertaken. Firstly, we compared the reactivity of the perovskites prepared following the two different processes secondly, a comparison was made for the sol-gel preparation between the flash and the conventionally calcined samples. The following points were noted ... 

Ghasdi, M., Alamdari, H., Royer, S., and Adnot, A. (2011) Electrical and CO gas sensing properties of nanostructured Lai ,Ce ,Co03 perovskite prepared by activated reactive synthesis. Sens. 

Rossetti, 1. and Forni, L. (2001) Catalytic flameless combustion of methane over perovskites prepared by flame hydrolysis. Appl Catal B, 33 (4), 345-352. 

Zou, G Chen, L and Wang, X. (2008) Properties and catalytic performance for methane combustion of LaMnOa perovskite prepared in oil-water two-phase system. Catal, Lett, 126, 96-99. 

Forni and Rossetti studied Lao-oCeo-iCoOs+a perovskites prepared by the flame hydrolysis (FH) method [27]. This was proved a high-surface-area, thermally resistant catalyst The partial substitution of La by Ce in such a cobaltite led to a relatively low suprafacial activity, but to a high bulk oxygen mobility, leading to high intrafacial activity for the catalytic flameless combustion of methane. 

Figure 17.6 SEM micrographs of LaMnOs+s perovskites prepared by combustion method using glycine/nitrate ratios of 0.8 (a) and 0.43 (b). (Reprinted with permission from Ref. [22]. Copyright 2011, Elsevier.)...

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