Water Durable Electride Y5Si3: Electronic Structure and Catalytic Activity for Ammonia Synthesis

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• 作者：Yangfan Lu ; Jiang Li ; Tomofumi Tada ; Yoshitake Toda ; Shigenori Ueda ; Toshiharu Yokoyama ; Masaaki Kitano ; Hideo Hosono
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：March 30, 2016
• 年：2016
• 卷：138
• 期：12
• 页码：3970-3973
• 全文大小：332K
• ISSN：1520-5126

文摘

We report an air and water stable electride Y₅Si₃ and its catalytic activity for direct ammonia synthesis. It crystallizes in the Mn₅Si₃-type structure and confines 0.79/f.u. anionic electrons in the quasi-one-dimensional holes. These anionic electrons strongly hybridize with yttrium 4d electrons, giving rise to improved chemical stability. The ammonia synthesis rate using Ru(7.8 wt %)-loaded Y₅Si₃ was as high as 1.9 mmol/g/h under 0.1 MPa and at 400 °C with activation energy of ∼50 kJ/mol. Its strong electron-donating ability to Ru metal of Y₅Si₃ is considered to enhance nitrogen dissociation and reduce the activation energy of ammonia synthesis reaction. Catalytic activity was not suppressed even after Y₅Si₃, once dipped into water, was used as the catalyst promoter. These findings provide novel insights into the design of simple catalysts for ammonia synthesis.