Effect of Impurity Silica on Grain Boundary Resistance of Yttrium-doped Barium Zirconate

Abstract

The concentrations of impurities in BaZroesYo ΐ5θ 3 . δ were qualitatively measured by GD-MS, and the concentrations of carbon, nitrogen, sodium, silicon, sulfur, chlorine, hafnium, and platinum were found to be more than 100 ppm. Among these identified impurities, we investigated the influence of sodium and silicon on grain boundary resistance of BaZrossYo 15Ο3.5. It was found that silica or silicate precipitated at grain boundary of BaZrossYo is0 3 . 5 and prevented the proton conduction of BaZr 0 8 5Yo ΐ5θ 3 . δ at the grain boundary, but sodium did not affect either bulk or grain boundary resistance. Also, we investigated which steps of the applied procedure causes the increase in the silicon concentration of BaZro^Yo ΐ5θ 3 . δ during the synthesis process of the widely-used solid state reaction method.Drying the powder in atmospheric air and using the heated glass flask were found to be major problems.With this knowledge, we reduced the silicon concentration of sintered BaZr 0 8 5Yo is0 3 . 5 to 120 ppm.

Aerosol method assisted fabrication Ag@SiO 2 and efficient catalytic activity for reduction of 4‐nitrophenol

“…However, the large surface energy of noble metal particles could easily lead to agglomeration phenomenon, resulting in a remarkable reduction in their catalytic activities, which restrict the development of precious metal materials seriously. Silica nanoparticles have attracted much attention due to the distinctive properties of the composites such as high tenacity [12], high temperature resistance [13], high specific surface area and so on. Therefore, silica has been identified as a good kind of catalyst carrier [14][15][16].…”