Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst function. Supported noble metal nanocatalysts such as platinum are of interest in fuel cells and as diesel oxidation catalysts for pollution control, and practical ruthenium nanocatalysts are explored for ammonia synthesis. Graphite and graphitic carbons are of interest as supports for nanocatalysts. Despite considerable literature on the catalytic processes on graphite and graphitic supports, reaction dynamics of the nanocatalysts on the supports in different reactive gas environments and operating temperatures at the single atom level are not well understood. Here we present real time in-situ observations and analyses of reaction dynamics of Pt in oxidation, and practical Ru nanocatalysts in ammonia synthesis, on graphite and related supports under controlled reaction environments using a novel environmental (scanning) transmission electron microscope with single atom resolution. By recording snapshots of the reaction dynamics, the behaviour of the catalysts is imaged. The images reveal single metal atoms, clusters of a few atoms on the graphitic supports and the support function. These all play key roles in the mobility, sintering and growth of the catalysts. The experimental findings provide new structural insights into reaction dynamics, morphology and stability of the nanocatalysts.

气体在工作温度下在原子水平上的反应动力学是气固催化剂非均相反应的基础，对催化剂功能至关重要。负载型贵金属纳米催化剂（例如铂）在燃料电池中很重要，并且作为柴油氧化催化剂以控制污染，并且探索了实用的钌纳米催化剂用于氨合成。石墨和石墨碳作为纳米催化剂的载体是令人感兴趣的。尽管有大量关于石墨和石墨载体上的催化过程的文献，但是对纳米催化剂在载体上的反应动力学在不同反应性气体环境中和在单原子水平下的操作温度的了解还不是很清楚。在这里，我们介绍了Pt在氧化反应中的实时原位观察和反应动力学分析，新颖的环境（扫描）透射电子显微镜和单原子分辨率，在受控的反应环境下，在石墨和相关载体上合成出了实用的氨合成钌纳米催化剂。通过记录反应动力学的快照，可以对催化剂的行为进行成像。图像揭示了单个金属原子，石墨载体上的几个原子簇和载体功能。这些都在催化剂的迁移率，烧结和生长中起关键作用。实验结果为纳米催化剂的反应动力学，形态和稳定性提供了新的结构见解。通过记录反应动力学的快照，可以对催化剂的行为进行成像。图像揭示了单个金属原子，石墨载体上的几个原子簇和载体功能。这些都在催化剂的迁移率，烧结和生长中起关键作用。实验结果为纳米催化剂的反应动力学，形态和稳定性提供了新的结构见解。通过记录反应动力学的快照，可以对催化剂的行为进行成像。图像揭示了单个金属原子，石墨载体上的几个原子簇和载体功能。这些都在催化剂的迁移率，烧结和生长中起关键作用。实验结果为纳米催化剂的反应动力学，形态和稳定性提供了新的结构见解。