Synthesis and properties of BaCe1−xYxO3−δ–BaWO4 composite protonic conductors

Abstract

Barium cerate doped by trivalent rare earth metal ions is a potentially huge component of materials for electrochemical industry due to its high protonic conductivity. However, the poor chemical stability especially in the presence of CO 2 , SO 2 or H 2 O, resulting in decreasing the mechanical durability of obtained materials, limits their possible applications. The new approach towards stable ceramic protonic conductors with high electrical conductivity is presented. Thermal stability of yttrium doped (10 mol%) of BaCeO 3 was enhanced by forming the composite material BaCe 0.9 Y 0.1 O 3 -BaWO 4 (10 mol% of BaWO 4 ). The synthesis was performed by solid-state reaction method. The detailed study of thermal decomposition of starting powders mixture was performed using thermogravimetry and differential thermal analysis (TG/DTA) techniques combined with Evolved Gas Analysis (EGAmass spectrometry). Structure, phase composition and microstructure together with thermal stability of sintered materials were determined. The exposition tests were performed to characterise the stability of composites in carbon dioxide and water vapour-rich atmospheres. The samples were exposed to atmosphere containing CO 2 /H 2 O (7 % of CO 2 in air, 100 % RH) at temperature of 25°C for 300 h. Thermal analysis supplied with mass spectrometry was applied to analyse the materials after the test. The results of this experiment showed better chemical resistance of composite material-BaCe 0.9 Y 0.1 O 3 with 10 mol% of BaWO 4 compared to single phase material.

Structure and thermal decomposition of ammonium metatungstate

“…One of their major applications is that tungsten oxides, metal tungstates, tungsten carbides or tungsten metal can be prepared from them, all of which are significant for various industries. Tungsten oxides can be used as catalysts [2][3][4][5], photocatalysts [6][7][8][9][10], gas sensors [11][12][13][14][15][16][17][18], chromogenic materials [19][20][21]; metal tungstates can be used among others as catalysts [22], pigments [23,24]; tungsten carbides are the hard components in cutting, drilling, tools [25][26][27] and they are also used as catalysts [28,29]; while tungsten metal is a key element in lighting industry [1,[30][31][32][33][34].…”

FABRICATION AND CHARACTERIZATION OF Fe-DOPED TUNGSTEN TRIOXIDE PHOTOELECTRODES IN AQUEOUS MEDIUM USING TUNGSTIC ACID AND FERROCENE AS STARTING MATERIALS

“…High crystalline WO 3 was obtained for 20% Fe-doped WO 3 and this effect can also be observed on Fe-doped TiO 2 [31]. The main peak was shifted to lower lattice parameters due to the size of ionic radii of Fe 2+ (0.064 nm) [39], which was larger than W 6+ (0.060) [40]. The shifted peak also suggested that Fe 2+ had successfully replaced some of the W 6+ in bulk WO 3 lattice and thus, Fe-doped WO 3 was successfully synthesized.…”

A Comparative Study of Conventional and Microwave Sintering of BaCe1 − xGdxO3 − δ Ceramic

“…This study is essentially expected to contribute towards the ongoing efforts to obtain dense ceramic products from nanometric particles for SOFCs based on the application of proton conductors. [14] 1400 °C/5 h Conventional solid-state reaction route [46,47] 1200 °C/6 h Conventional solid-state reaction route [48] 1200 °C/12 h Conventional solid-state reaction route [49] 1150 °C/2 h Conventional solid-state reaction route [50] 1350 °C/6 h Conventional solid-state reaction route [15] 1150 °С/2 h Conventional solid-state reaction route [51] 1350 °C/10 h conventional solid-state reaction route [52] 1350 •C/10 h Conventional solid state reaction route [53] 1400 °C/10 h Conventional solid state reaction route [54] 950 °C/2 h Polymeric precursors route This work…”