The Novel Synthesis of La_0.8Sr_0.2MnO₃ Using the Michael-Addition Directed Hydrogelation of Acrylates for Materials Synthesis (MADHAMS) Method

Abstract

This report describes the low-temperature synthesis of nanocrystalline perovskite oxide, La 0.8 Sr 0.2 MnO 3 (LSM), using the ammonium acrylate salt precursor gel method that employs 3,3′,3′′-nitrilotripropionic acid (NTP) as the gelling agent. Due to its high degree of hydrogen bonding with water, NTP can absorb many times its own weight of water to yield a viscous liquid. Subsequent pyrolysis converts the mixture to the desired metal oxides. This preparative method has several advantages such as homogeneity, excellent control of stoichiometry, ease of handling, lower heating times and temperatures, and the production of uniform particle size and distribution. The synthesis of the LSM is achieved in as little as 10 hours (400 °C) with uniform distribution of particles that are 25 nm in size.

New synthesis of nanopowders of proton conducting materials. A route to densified proton ceramics

“…The Michael addition reaction by neutralisation of ammonia by acrylic acid in water leads to generation in situ of the hydrogen bonded 3,3 0 ,3 00 -nitrilotripropionic acid [N(CH 2 CH 2 CO 2 H) 3 ] which complexes the metal acrylates and forms a hydrogel in which the metal ions are homogeneously distributed [35,37]. This mixture is converted to the corresponding metal oxides by pyrolysis.…”

“…The first stage between 30 and 180 1C results from loss of the adsorbed and structural water from the precursor gel, and is accompanied by an endothermic peak at in the DTA curve (at 125 1C in the zirconate precursor, 140 1C in the cerate precursor). The following step between 200 and 400 1C is related to the combustion and decomposition of the ammonium acrylate and 3,3 0 ,3 00 -nitrilotripropionic acid produced during the hydrogelation reaction, which is related to the peaks in the DSC curves at 230-240 1C and 330 1C, when polyacrylic acid is formed [35]. Crystallisation occurs above 400 1C and the mass remains constant for temperatures above 600 1C.…”

“…This method leads to homogenous nanoparticles and well-densified materials, but presents some shortcomings compared to the use of hydrogels prepared from metal acrylate precursors. Hydrogelation was described for preparation of electrode ceramics such as La 0.8 Sr 0.2 MnO 3 [35] but has never been adapted for the development of proton ceramic electrolytes. We also describe the structural, morphological, water uptake and proton conduction properties of BCY10 and BZY10 prepared using these routes.…”

Synthesis and Characterization of La<sub>0.8</sub>Sr<sub>0.2</sub>MnO<sub>3-δ</sub> Nanostructures for Solid Oxide Fuel Cells

“…3,3',3"-Nitrilotripropionic acid (NTP) was synthesized using a green chemical method [18]. 3.37 g of lanthanum nitrate (La(NO 3 ) 3 ), 0.55 g of strontium nitrate (Sr(NO 3 ) 2 ) and 2.32 g of manganese nitrate (Mn(NO 3 ) 2 ) were slowly dissolved in 75 mL distilled water.…”

3-(2-Acetylanilino)propanoic acid

“…For general background, see: Crosby et al (1961Crosby et al ( , 1962; Foley et al (2003) ;Walker Jr et al (2004); Yoshihara et al (2001). For related structures, see: Slater et al (2006).…”