Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany.
Fachbereich Physik, Universität Hamburg, 20355 Hamburg, Germany.
Phys Rev Lett. 2018 Mar 23;120(12):126101. doi: 10.1103/PhysRevLett.120.126101.
Pt-Rh alloy nanoparticles on oxide supports are widely employed in heterogeneous catalysis with applications ranging from automotive exhaust control to energy conversion. To improve catalyst performance, an atomic-scale correlation of the nanoparticle surface structure with its catalytic activity under industrially relevant operando conditions is essential. Here, we present x-ray diffraction data sensitive to the nanoparticle surface structure combined with in situ mass spectrometry during near ambient pressure CO oxidation. We identify the formation of ultrathin surface oxides by detecting x-ray diffraction signals from particular nanoparticle facets and correlate their evolution with the sample's enhanced catalytic activity. Our approach opens the door for an in-depth characterization of well-defined, oxide-supported nanoparticle based catalysts under operando conditions with unprecedented atomic-scale resolution.
在负载型金属纳米粒子催化剂中，负载在氧化物载体上的 Pt-Rh 合金纳米粒子由于其在汽车尾气处理和能量转化等方面的应用而受到广泛关注。为了提高催化剂的性能，需要在工业相关的反应条件下，从原子尺度上关联纳米粒子表面结构与其催化活性。在这里，我们通过在近常压 CO 氧化反应中结合使用 X 射线衍射和原位质谱，提供了对纳米粒子表面结构敏感的 X 射线衍射数据。我们通过检测特定纳米粒子晶面的 X 射线衍射信号，来识别超薄表面氧化物的形成，并将其演化与样品增强的催化活性相关联。我们的方法为在反应条件下对具有原子级分辨率的具有明确定义的氧化物负载型纳米粒子基催化剂进行深入表征开辟了道路。
