Preparation of double-doped BaCeO₃and its application in the synthesis of ammonia at atmospheric pressure

Abstract

Perovskite-type oxides BaCe 0.90 Sm 0.10 O 3Àd (BCS) and BaCe 0.80 Gd 0.10 Sm 0.10 O 3Àd (BCGS) were synthesized by the sol-gel method and characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Using the sintered samples as solid electrolytes and silver-palladium alloy as electrodes, ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in a solid-state proton-conducting cell reactor. The maximum rate of production of ammonia was 5.82 Â 10 À9 mol s À1 cm À2 .

Effect of strontium on Nd doped Ba 1− x Sr x Ce 0.65 Zr 0.25 Nd 0.1 O 3− δ proton conductor as an electrolyte for solid oxide fuel cells

“…The weight loss from 500–1000 °C and the exothermic peaks near 900 °C are due to co-oxidation. A very small weight loss was observed above 1000 °C, which is due to thermal decomposition of barium carbonate, with the release of CO 2 for all the samples [27], [28]. This finding is consistent with the XRD results that Ba 1− x Sr x Ce 0.65 Zr 0.25 Nd 0.1 O 3− δ phase only forms upon calcined at 1000 °C and above.…”

Progress in the Electrochemical Synthesis of Ammonia

“…In the past decade, many researchers have tested the activity of AgPd. Li et al used barium cerates (BCS, BCGS) as electrolytes and reported reaction rates as high as 5.82 × 10 −9 mol s −1 cm −2 [18]. Using a lanthanum-doped cerium oxide electrolyte (LDC), Liu et al obtained a reaction rate of 8.2 × 10 −9 mol s −1 cm −2 [35].…”

Ammonia synthesis at atmospheric pressure in a BaCe0.2Zr0.7Y0.1O2.9 solid electrolyte cell

“…In 1998, however, ammonia was synthesized electrochemically from gaseous N 2 and H 2 at atmospheric pressure and at temperatures near 550°C using a proton conducting solid electrolyte cell [5]. Since this first work on "solid-state ammonia synthesis" (SSAS), several research groups have studied this reaction system and have identified the problems that must be solved in order to promote SSAS into industrial practice [6][7][8][9][10][11][12][13]. More than 30 solid electrolyte materials have been tested and at least 15 catalysts have been used as working electrodes [3].…”