In situ formation of Ru nanoparticles on La_1−x Sr _x TiO₃-based mixed conducting electrodes and their application in electrochemical synthesis of ammonia using a proton-conducting solid electrolyte

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• 作者：Fumihiko Kosaka ; Naoto Noda ; Takehisa Nakamura…
• 刊名：Journal of Materials Science
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：52
• 期：5
• 页码：2825-2835
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Materials Science, general; Characterization and Evaluation of Materials; Polymer Sciences; Continuum Mechanics and Mechanics of Materials; Crystallography and Scattering Methods; Classical Mechanics;
• 出版者：Springer US
• ISSN：1573-4803
• 卷排序：52

文摘

In situ formation of highly dispersed 2–5 nm Ru nanoparticles was successfully achieved in highly Ru-doped (40% Ru) perovskite cathode material, Ru-doped La_0.3Sr_0.6TiO₃ (LSTR), used for electrochemical ammonia synthesis in a proton-conducting fuel cell (PCFC). Highly dispersed Ru nanoparticles were observed by exsolution of doped Ru from the B-site in the LSTR perovskite lattice under PCFCs operating conditions, that is, a reducing atmosphere, without agglomeration, which is difficult to achieve with a conventional impregnation method. The particle size and dispersion were successfully controlled by reduction temperature and Ru doping amount. The optimized microstructure was finally adopted for the electrochemical synthesis of ammonia with BaCe_0.9Y_0.1O₃ solid electrolyte at 500 °C. Ammonia formation using a 40% Ru-doped LSTR (LSTR40) cathode was observed by applying cathodic overpotentials. The maximum ammonia formation rate using the LSTR40 cathode was 3.8 × 10−12 mol s−1 cm−2 at −0.1 V. The results suggest that Ru nanoparticles exsoluted from the LSTR perovskite act as a active site effectively for the electrochemical reaction.