Chemical & Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA.
Phys Chem Chem Phys. 2012 May 21;14(19):6688-97. doi: 10.1039/c2cp40121e. Epub 2012 Apr 4.
CO oxidation was carried out over Ru(0001) and RuO2(110) thin film grown on Ru(0001) at various O2/CO ratios near atmospheric pressures. Reaction kinetics, coupled with in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRAS) and post-reaction Auger electron spectroscopy (AES) measurements, were used to identify the catalytically relevant phases under different reaction conditions. Under stoichiometric and reducing conditions at all reaction temperatures, as well as net-oxidizing reaction conditions below ∼475 K, a reduced metallic phase with chemisorbed oxygen is the thermodynamically stable and catalytically active phase. On this surface CO oxidation occurs at surface defect sites, for example step edges. Only under net-oxidizing reaction conditions and above ∼475 K is the RuO2 thin film grown on metallic Ru stable and active. However, RuO2 is not active itself without the existence of the metal substrate, suggesting the importance of a strong metal-substrate interaction (SMSI).
在接近大气压力的各种 O2/CO 比下，在 Ru(0001) 上生长的 Ru(0001) 和 RuO2(110) 薄膜上进行了 CO 氧化。反应动力学，结合原位极化调制红外反射吸收光谱 (PM-IRAS) 和反应后俄歇电子能谱 (AES) 测量，用于在不同反应条件下识别催化相关相。在所有反应温度下的化学计量和还原条件下，以及在约 475 K 以下的净氧化反应条件下，具有化学吸附氧的还原金属相是热力学稳定和催化活性相。在这个表面上，CO 氧化发生在表面缺陷部位，例如台阶边缘。只有在净氧化反应条件下且高于约 475 K 时，生长在金属 Ru 上的 RuO2 薄膜才稳定且具有活性。然而，没有金属基底的存在，RuO2 本身没有活性，这表明强金属-基底相互作用 (SMSI) 的重要性。
