Efficient ammonia synthesis and decomposition processes under mild conditions are important to meet the expanding demand in major applications of ammonia as the energy carrier and to provide feedstock for chemical industry. Here, we report that air-stable calcium cyanamide-supported ruthenium (Ru/CaCN₂) works as an efficient and stable catalyst for ammonia synthesis and decomposition. Ru/CaCN₂ exhibits greater catalytic performances for both reactions than Ru/Ca₂N electride and Ru–Cs/MgO. The kinetic analysis for ammonia synthesis suggests that Ru/CaCN₂ exhibits low apparent activation energy and high resistance to hydrogen poisoning, which has characteristics similar to the kinetic parameters of Ru-supported electride catalyst. H₂-temperature programmed reaction and temperature programmed desorption revealed that Ru promoted the formation of CN₂ vacancies on the CaCN₂ surface which in turn capture hydrogen as H^– ions during the reaction. Density functional theory calculations provide insights into how the formation of CN₂ vacancies is promoted by Ru, which leads to the decrease in the work function of the CaCN₂ surface and the hydrogen capture at the Ru-support interface. These results suggest that the high catalytic performance of Ru/CaCN₂ can be attributed to the formation of a quasi-electride structure at the Ru–CaCN₂ interface.

中文翻译：

---

空气稳定的氰氨化钙负载钌催化剂用于氨的合成和分解

在温和的条件下有效的氨合成和分解过程对于满足氨作为能源载体的主要应用中不断增长的需求以及为化学工业提供原料至关重要。在这里，我们报告说，空气稳定的氰氨化钙负载钌（Ru / CaCN ₂）是合成氨和分解氨的有效且稳定的催化剂。Ru / CaCN ₂在两个反应中均显示出比Ru / Ca ₂ N氮化物和Ru-Cs / MgO更高的催化性能。对氨合成的动力学分析表明，Ru / CaCN ₂表现出低的表观活化能和高的抗氢中毒性，其特性类似于Ru负载的电子催化剂的动力学参数。H₂ -温度控制的反应和程序升温脱附表明，钌促进CN的形成₂的CACN上空缺₂表面继而捕获氢以H ^-在反应过程中的离子。密度泛函理论计算提供了有关Ru如何促进CN ₂空位形成的见解，这导致CaCN ₂表面的功函数降低以及Ru-载体界面处的氢捕获。这些结果表明，Ru / CaCN ₂的高催化性能可以归因于在Ru–CaCN ₂界面处形成准电氮化物结构。