Sol—Gel Synthesis of Strontium‐Doped Lanthanum Manganite

Abstract

Strontium‐doped lanthanum manganite powders were prepared using a peroxide acetate salt based solution. The stable sol was peptized by reacting ammonium hydroxide with the precursor solution. The amorphous dried gel powders exhibit a high energy level, due to their high cations coordination and small particles, to develop the perovskite phase. This crystalline phase development from powders containing monocarboxylate ligands was characterized by thermal analysis (TG, DTG, DTA), X‐ray diffraction, and IR spectroscopy. The transformation from amorphous powders into a crystallized homogeneous oxycarbonate phase in a first stage corresponds to an exothermal DTA peak at 270°C. X‐ray diffraction patterns and IR spectra showed similar behavior of the powders after complete organic removal, during the conversion into perovskite phase starting at approximately 630°C and achieved about 700°C and achieved about 700°C, as well as during the sintering process.

Synthesis of biodiesel from Jatropha curcas L. seed oil using artificial zeolites loaded with CH3COOK as a heterogeneous catalyst

“…On the other hand, the intensity of the abso0rption at 3440cm -1 decreased at higher calcination temperatures (curves d, f and g), indicating a decrease in basic sites, in line with Hammett basicity measurement ( Table 2). The absorption peak at 1552cm -1 can be assigned to asymmetric vibration of COO - [28] of CH 3 COOK (curve e), which disappeared after calcination at 823K (curve d), demonstrating that CH 3 COOK decomposed completely after calcination at 823 K. In addition, there were some other absorption peaks at 400-1400cm -1 for all samples, which can be attributed to Al-O (or Si-O) symmetric stretching and ring vibration in Al-O and Si-O tetraheda formed through the oxygen atom.…”

Synthesis of La1−xSrxMnO3 cubic crystals with adjustable doping levels

“…In this paper, La 1Àx Sr x MnO 3 with adjustable doping levels has been synthesized. Additionally, up to now, CMR materials were mainly prepared by the conventional solid-state reaction method [5]and sometimes by sol-gel method [6,7]. As far as the former method is concerned, it needs high temperature about 1400 1C and large equipment, and it is sometimes difficult to obtain pure phase due to incompletion of the reaction.…”

Catalytic behavior of hydrothermally synthesized La0.5Sr0.5MnO3 single-crystal cubes in the oxidation of CO and CH4

“…These solids, widely used as oxidation catalysts and as cathode materials in solid-oxide fuel cells, have been studied intensively [5,6]. They were prepared mainly using high-temperature ceramic, coprecipitation, citrate, and sol-gel routes [7][8][9][10]. The obtained materials are usually composed of assorted polycrystals with various exposed crystal planes that could exhibit the different catalytic activities.…”